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UNIVERSITY OF ILLINOIS LIBRARY AT URBANA-CHAMPAIGN
FEB P j 2(|05
NOV 1 9 2007
Field Guide
to
Silkmoths of Illinois
John K. Bouseman
James G. Sternburg
Also by the same authors
Field Guide to Butterflies of Illinois:
Illinois Natural History Survey Manual 9
Field Guide
to
Silkmoths of Illinois
John K. Bouseman
James G. Sternburg
Illinois Natural History Survey • Champaign
September 2002
Manual 10
Illinois Natural History Survey, David L. Thomas, Chief
A Division of the Illinois Department of Natural Resources,
Brent Manning, Director
Illinois Natural History Survey
Natural Resources Building
607 East Peabody Drive
Champaign, Illinois 61820
Printed by the authority of the State of Illinois
Photo credits: All photographs are by James G. Stemburg unless
otherwise indicated in the figure captions. Copyright of each photo
resides with the photographer.
Editors: Thomas E. Rice and Charles Warwick
Dust jacket: Thomas E. Rice
ISBN: 1-882932-06-4
Library of Congress Control Number: 2002108786
Citation:
Bouseman, J.K., and J.G. Stemburg. 2002. Field guide to silkmoths of Illinois. Illinois
Natural History Survey Manual 10. x + 97 pp.
Printed with soy ink on recycled and recyclable paper.
Equal opportunity to participate in programs of the Illinois Department of Natural
Resources (IDNR) and those funded by the U.S. Fish and Wildlife Service and other
agencies is available to all individuals regardless of race, sex, national origin, disability,
age, religion, or other non-merit factors. If you believe you have been discriminated
against, contact the funding source’s civil rights office and/or the Equal Employment
Opportunity Officer — IDNR, One Natural Resources Way, Springfield, IL 62702-1271;
217/785-0067; TTY 217/782-9175.
IV
This work is dedicated to those amateur and professional
entomologists, past and present, whose endeavors have helped to
make this field guide possible.
Adams 40
Alexander 100
Bond 70
Boone 4
Brown 42
Bureau 17
Calhoun 60
Carroll 7
Cass 44
Champaign 49
Christian 55
Clark 63
Clay 78
Clinton 76
Coles 66
Cook 11
Crawford 74
Cumberland 67
De Kalb 9
DeWitt 47
Douglas 58
Du Page 12
Edgar 59
Edwards 85
Effingham 72
Fayette 71
Ford 38
Franklin 89
Fulton 33
Gallatin 95
Greene 61
Grundy 20
Flamilton 90
Flancock 31
Hardin 99
Henderson 23
Henry 16
Iroqouis 39
Jackson 92
Jasper 73
Jefferson 83
Jersey 62
Jo Daviess 1
Johnson 97
Kane 10
Kankakee 30
Kendall 19
Knox 25
Lake 6
La Salle 18
Lawrence 80
Lee 14
Livingston 29
Logan 46
Macon 56
Macoupin 63
Madison 69
Marion 77
Marshall 28
Mason 43
Massac 102
McDonough 32
McHenry 5
McLean 37
Menard 45
Mercer 22
Monroe 81
Montgomery 64
Morgan 53
Moultrie 57
Ogle 8
Peoria 34
Perry 88
Piatt 48
Pike 51
Pope 98
Pulaski 101
Putnam 27
Randolph 87
Richland 79
Rock Island 15
St. Clair 75
Saline 94
Sangamon 54
Schuyler 41
Scott 52
Shelby 65
Stark 26
Stephenson 2
Tazewell 35
Union 96
Vermilion 50
Wabash 86
Warren 24
Washington 82
Wayne 84
White 91
Whiteside 13
Will 21
Williamson 93
Winnebago 3
Woodford 36
Illinois County
Locations
vi
Contents
Illinois County Locations (map) vi
Foreword ix
Acknowledgments x
Introduction 1
How to Use This Book 2
Maps of Distribution 2
Economic Considerations 2
Classification 3
Larval Morphology 4
Wing Expansion 8
Mimicry 10
Rearing Saturniids 11
Photographing Insects 12
Saturniid Relatives 14
Species Accounts 15
Regal Moth or Royal Walnut Moth — Subfamily Ceratocampinae 17
Pine-devil Moth — Subfamily Ceratocampinae 22
Imperial Moth — Subfamily Ceratocampinae 24
Spiny Oakworm Moth — Subfamily Ceratocampinae 28
Pink-striped Oakworm Moth — Subfamily Ceratocampinae 30
vii
Orange-striped Oakworm Moth — Subfamily Ceratocampinae 32
Rosy Maple Moth — Subfamily Ceratocampinae 34
Bisected Honey Locust Moth — Subfamily Ceratocampinae 36
Honey Locust Moth — Subfamily Ceratocampinae 38
Buck Moth — Subfamily Hemileucinae 41
Nevada Buck Moth — Subfamily Hemileucinae 43
lo Moth — Subfamily Hemileucinae 45
Polyphemus Moth — Subfamily Satumiinae 48
Luna Moth — Subfamily Saturniinae 53
Promethea Moth or Spicebush Silkmoth — Subfamily Satumiinae 58
Tulip Tree Silkmoth — Subfamily Saturniinae 64
Cecropia Moth or Robin Moth — Subfamily Saturniinae 69
Columbia Silkmoth — Subfamily Satumiinae 75
Ailanthus Silkmoth — Subfamily: Satumiinae 80
Glossary 83
Species Checklist 85
Additional Reading 87
Index 93
vm
Foreword
The authors have been encouraged and heartened by the reception of our
Field Guide to Butterflies of Illinois. Although very authoritative and compre¬
hensive treatments existed for the butterflies of North America, we have found
that an audience existed for regional manuals. Faunal works of limited and
perhaps arbitrary scope reduce for the casual observer the “noise" generated by
extraneous faunal elements in groups of confusingly similar species that can be
difficult to determine.
In this book we treat the often spectacularly large and beautiful moths
known as the imperial moths or silkmoths. Both the adults and larvae of these
insects have long attracted the attention of naturalists, scientists, artists, school-
children, and people in general.
We have recently become aware of reports that these heretofore rather
common insects are suffering catastrophic population declines. These losses in
some parts of the country have been atttributed to the depredations of a parasitic
fly, Compsilura concinnata, which was imported and introduced into North
America from Europe as a component of biological control programs targeted at
the gypsy moth and other forest pest species. We are saddened by this calami¬
tous development and further dismayed by the prospect of the possible extermi¬
nation of these awesomely beautiful creatures by an introduced generalist
predator.
John K. Bouseman and James G. Stemburg
IX
Acknowledgments
We are indebted to many persons for their interest in the production of this book
and for the kind aid they provided to us in the course of its preparation. Tim
Cashatt and Jim Wiker helped us search the collection of the Illinois State
Museum for records of moths. Jim Wiker also helped by allowing us to photo¬
graph specimens from his magnificent personal collection of Lepidoptera. We
enjoyed the hospitality of the Richardson Wildlife Foundation where we were
able to work on the manuscript away from the usual daily distractions of life in
Urbana. For this we thank Edward J. Richardson, president of the foundation,
and Terry Moyer, vice president and resident manager of the facility. Carie
Nixon prepared excellent line drawings for the book. University of Illinois
entomologists Jim Appleby and Phil Nixon made some much-needed slides
available to us, as did James Tuttle of Tuscon, AZ. The manuscript was
carefully typed by Dottie Nadarski. Liane Suloway prepared the distributional
maps. As always, we were enormously benefited by the superb redactional
skills of our editors at the Natural History Survey, Charles Warwick and
Thomas Rice. INHS Head Librarian Elizabeth Wohlgemuth and staff librarians
JoAnn Jacoby and Jessica Beverly cheerfully sought out elusive references and
rare volumes. May Berenbaum and Gilbert Waldbauer of the University of
Illinois Department of Entomology and Tim Cashatt of the Illinois State
Museum provided thorough, helpful reviews of the initial draft of this publica¬
tion. We heartfully thank all of the above for their indispensable aid.
The authors wish to thank their respective parents, Thomas and Catherine
Bouseman and Paul and Eva Sternburg, for their encouragement of our early
interest in collecting and rearing moths. JKB thanks Tammie and William
Bouseman for their aid in the field.
x
Introduction
The purpose of this field guide is to enable the user to identify to species any
member of the moth family Satumiidae found in the state of Illinois. Second¬
arily, a selection of literature is offered that will serve to introduce the reader to
the voluminous published work that exists about these often spectacularly
beautiful insects.
Of the 23 native and one introduced species of satumiid moths that are
known from North America east of the Mississippi River, all save 6 have been
recorded from Illinois. Those missing are species of limited range in either the
southern or northeastern United States. Thus, this field guide should serve well
throughout most of the eastern United States.
Because satumiid moths are for the most part nocturnal insects of forests
and of somewhat obscure habits, they are not observed as frequently as their
diurnal relatives such as butterflies and skippers. As a consequence, their
distributions tend not to be well known. Indeed, they are generally noticed only
when attracted to lights.
We hope that this summary of what is known about these moths in Illinois
will challenge readers to add to our somewhat scanty knowledge of them.
l
Field Guide to Silkmoths of Illinois
How to Use This Book
The user should become familiar with the characteristics that enable one to
recognize a satumiid moth. This is especially important in dealing with the
smaller species. Most of the larger species are recognizable at a glance because
of their size and unique patterns. Comparison with the illustrations of speci¬
mens in the text should lead to the rapid identification of any saturniid moth
found in Illinois.
Under the individual species accounts, there are descriptions of the adults
and the immature stages (larvae and pupae). If there is the possibility of
confusion among various species, this is discussed under “Similar Species.”
There is a discussion of the “Habitats” where the species is likely to be encoun¬
tered and the “Life Histories” are treated for all species. Our opinion of the
geographic distribution is given under “Status.” “Remarks” will add various
sorts of information that do not fit comfortably under the other rubrics.
Maps of Distribution
The distributions of the silkmoths and royal moths known to occur in Illinois are
indicated on the maps that accompany the individual species accounts and are
presented in the form of county records. These records have been compiled
from specimens in the collection of the Illinois Natural History Survey supple¬
mented by records from the Illinois State Museum, from the personal experience
of the authors, and from published records. The main sources of published
records are Paul A. Opler’s Distribution of Silkmoths ( Saturniidae ) and Hawk-
moths ( Sphingidae ) of Eastern North America and the “Season Summaries” in
the newsletters of the Lepidopterists’ Society.
The absence of a record from any particular county should not necessarily
be interpreted to mean that a species does not occur in that county. It could
simply mean that no amateur or professional entomologist has searched for or
collected that species in the county. The maps are indicative, not definitive, of
the ranges of the species.
Economic Considerations
A few of the species treated in this book have minor status as economic pests
through their occasional defoliation of forest trees. Included among such are the
oakworms of the genus Anisota and the Rosy Maple Moth. These infestations
are generally of short duration.
The larvae of the buck moths and the Io Moth are of medical importance
because of their vestiture of urticating (stinging) setae. In contact with bare
skin, they cause a severe nettling sensation. They should be handled with
considerable caution.
2
Classification
Classification
The family Satumiidae, along with eight other families of moths, constitute the
superfamily Bombycoidea of the order Lepidoptera. Only two of these nine
families, the
Saturniidae and the
Sphingidae, are
well represented in
North America.
Five species of the
subfamily
Apatelodinae of the
family Bombycidae
occur in the eastern
United States. All
of the other
bombycid subfami¬
lies and the other
six bombycoid
families are of
exotic occurrence.
They are mainly
Palaearctic species
of Eurasian
distribution.
Family
Saturniidae.
Satumiids are
medium to large
moths, most with
stout bodies that
are densely clothed
with fine, hairlike
setae. The head is
small, closely Moth antennae,
attached to the
thorax. The labial palps are present but small. The proboscis is reduced or
absent and not functional; these moths never feed or drink as adults. Compound
eyes are often large in nocturnal species, smaller in some of the diurnal species.
There are no ocelli. The antennae of most males are quadripectinate, with long
rami (branches). An exception occurs in the buck moths of the genus Hctnilcucci
where the antennae are bipectinate. Females have either quadripectinate
antennae with reduced rami or bipectinate or simple antennae, depending on the
3
Field Guide to Silkmoths of Illinois
species. In all species the forewing
has wing vein Cu appearing to be
three-branched. The hindwing has
Rs widely separated from wing
veins Sc + Ri. All satumiids lack a
frenulum. To keep the fore and
hindwings together in flight, the
humeral angle of the hindwing is
expanded, and extends forward
below the forewing. This is called
amplexiform coupling, a condition
evolved independently in the
butterflies and a few other families
of moths. Both nocturnal and
diurnal species occur. In Illinois,
the male Promethea Moth is
diurnal, whereas the female is
nocturnal. Both sexes of buck
moths of Illinois are diurnal. Two
of our Anisota species have diurnal
males.
Humeral
Abbreviation of wing vein terms
A
anal vein
R,
first branch of radius
C
costa
R R 5
divisions of the radial sector
Sc
subcosta
M
media
R
radius
M, to M^
divisions of the median vein
Rs
radial sector
Cu
cubitus
Larval Morphology
Satumiid larvae have the typical structures found in the order Lepidoptera. The
body is divided into three regions: head, thorax, and abdomen. The head
consists of two preoral regions and four postoral segments fused together to
form a cranium with stemmata (larval eyes), antennae, labrum, mandibles,
maxillae, and labium. The two antennae are very small. On each side of the
head there is a semicircular cluster of stemmata, the larval eyes. The paired
mandibles, paired maxillae, and the labium — a fusion of second maxillae — are
typical of insects with chewing mouthparts. Mandibles are not present in the
pupal or adult stages of Lepidoptera (Note: A few primitive moths retain
4
Classification • Larval Morphology
mandibles as adults). The thorax consists of three segments — a prothorax, a
mesothorax, and a metathorax — each with a pair of segmented legs. The
abdomen has 10 segments, with paired fleshy prolegs on abdominal segments 3,
4, 5, 6, and 10. The prolegs bear minute hooks called crochets that enable the
larva to cling to the substrate. The head capsule is hard, whereas the thorax and
abdomen are soft and flexible. Spiracles through which air enters and leaves the
internal respiratory tracheal system are present on the lateral sides of the
prothorax and the first eight abdominal segments.
To aid the reader in identifying the saturniid larvae found in the environ¬
ment, it is necessary to define and illustrate the cuticular structures and their
location on the larvae. Saturniid larvae are easily recognized by their rows of
scoli, tuberous outgrowths of the thorax and abdomen. There are none on the
head. The few other caterpillars with scoli that might be confused with the
Reared Hickory Homed Devil larva, Pope County.
Reared Columbia Silkmoth larva, Lower Michigan.
5
Field Guide to Silkmoths of Illinois
saturniids are found in some of the butterflies (family Nymphalidae) and several
families of moths, including the slug caterpillar moths (family Limacodidae),
and some of the measuring worms (family Geometridae). Slug caterpillars have
spiny scoli extending outward along the lateral margins of the segments. Some
nymphalid larvae have numerous scoli, including some on the head; their
arrangement differs from that of the saturniids. Geometrid larvae have a
reduced number of ventral prolegs, unlike the saturniids, so they are easily
distinguished from saturniids.
Scoli (singular scolus) are sclerotized spiny outgrowths of the integument.
The form can be a tubercle with a seta or with a spine, often branched. Scoli of
the subfamily Hemileucinae are wartlike with piercing bristles that release and
inject an irritating and allergenic substance when the larva is attacked by a
predator. Scoli on the attacine Satumiinae are knoblike, or rounded, and often
colorful, with many spines; they lend a disruptive appearance to the larva. Scoli
are sometimes hornlike, more or less elongate, threatening in appearance but
actually harmless. This type occurs on many of the royal moths (subfamily
Ceratocampinae.) Scoli of the first instar larvae are usually larger in proportion
to body size than in the later instars, in some instances strikingly so. In some
larvae, for example in larvae of Actias luna and Antheraea polyphemus, the scoli
of the mature larvae are very small and easily overlooked.
Scoli in the Satumiidae are arranged in longitudinal rows of one per
thoracic and abdominal segment. Their locations are dorsal, subdorsal, and
subspiracular (or lateral). Thus, there are paired dorsal scoli, and on each side a
subdorsal and a subspiracular scolus. On the thoracic segments there may be a
lateroventral scolus.
In addition to the scoli, there are in some species small raised cuticular
granules, scattered more or less densely over the body surface, as in species of
the genus Anisota. All larvae have setae, with definite locations, some occurring
alone in the first instar and called primary setae. Others appear in the later
instars. In most saturniids all setae are short and not at once noticeable. How¬
ever, there are exceptions; for example, in larvae of Eacles imperialism where the
setae are very long and somewhat dense, giving the insect a hairy look.
Subfamily Ceratocampinae. Members of the subfamily Ceratocampinae are
known as the royal moths. The antennae are quadripectinate in the basal one-
half to two-thirds only, the outer part simple. The abdomen is as long as the
hindwings or longer. At rest, most of our species hold the wings in a flexed
position over the abdomen. An exception is Eacles, which rests with the wings
widespread. Larvae have at least one pair of thoracic scoli modified as long
hornlike structures. Pupation is in the soil, with no cocoon. Pupae are smooth
or rugose, or spiny with a prominent cremaster.
Subfamily Hemileucinae. Here are included the buck moths and Io Moth. The
6
Lan’al Morphology
Moth pupae. Polyphemus
antennae of males are either bipectinate or quadripectinate all the way to the tip.
If quadripectinate, the outer pair of rami touch the inner pair of the next seg¬
ment. Females have either simple or bipectinate antennae with short rami.
Larvae have scoli with urticating spines or hairlike setae, releasing a toxin when
broken that is extremely irritating, causing a burning sensation and rash. Both
sexes of the two buck moths are diurnal, while those of the Io Moth are noctur¬
nal. Larvae of buck moths and the Io Moth spin cocoons in or under the leaf
litter below the larval host plant.
Subfamily Saturniinae. These are large to very large moths, often very
colorful, or cryptic, or with prominent eyespots on the wings. The antennae of
both sexes are quadripectinate to the tips, with long rami in the males, and much
7
Field Guide to Silkmoths of Illinois
shorter rami in the females. At rest, depending on the species, the wings are
held open but not flexed (Luna Moth), or simply folded together and not flexed
above the body, resembling the true butterflies in this habit. The adults of most
are nocturnal. An exception among the Illinois species is found in the
Promethea Moth, where the males are diurnal in flight and mating, the females
diurnal in mating, and nocturnal in flight and oviposition. Larvae have well-
developed scoli, both lateral and dorsal in position. Our species do not have
urticating hairs, although these are present on a few species found elsewhere.
Larvae of the Cecropia Moth may attain a body weight of 20 grams or more.
Larvae spin strong silken cocoons, sometimes on the larval host, but often on a
nearby support where the cocoon can be hidden from predators. The structure of
the cocoon varies, some being relatively simple with no escape valve, to others
that are complex and double-walled with an escape valve.
Wing Expansion
Upon escape from the cocoon, the teneral (recently molted, still soft) adult
climbs quickly up a branch or tree trunk to find a spot that will allow the rapidly
expanding, thick, small, soft wings to hang down so that they can properly
assume the adult wing shape. Wing expansion is due to the positive pressure of
blood pumped into the wings, forcing the still-soft tissues to stretch. Within a
short time (15 minutes, more or less), the wings assume their final size. In the
case of the Luna Moth, the long tails are the last part to fully expand. Biochemi¬
cal action then hardens the wings. We show a series of photographs (pages 8-9) of
the wing expansion of a Luna Moth, from the time of emergence from the cocoon to the
final positioning of the fully formed and sclerotized (hardened) wings. This phase of
8
Wing Expansion
5
9
Field Guide to Silkmoths of Illinois
the moth’s life is in many ways the most critical. If the wings do not expand
properly, the insect will be unable to fly normally. If the moth is found by a
predator at this stage while still soft, it is defenseless, easy prey for a predator.
Mimicry
The diurnal males of Callosamia promethea are largely black, and in flight
resemble any of our blackish swallowtails, including the toxic Pipevine Swal¬
lowtail ( Battus philenof). The resemblance includes, to our eye, their wingbeat
frequency, their speed, and their general appearance in flight. A male
Promethea Moth in search of a pheromone-releasing female has a deliberate
flight, not stopping in search of nectar or other energy sources, and, from our
experience, can be mistaken for a swallowtail. The behavioral characteristics
are an integral part of the resemblance, not at once apparent when viewing a
dead museum specimen. Nevertheless, field experiments with live Promethea
Moths painted to resemble palatable and unpalatable insects have convincingly
shown the survival value of appearing to be an insect known to be toxic and
unpalatable to birds. Captive naive birds have been found to eat Promethea
Moths without ill effects, thus the mimicry must be Batesian (see Glossary for
definition).
It has been suggested (see Ferguson 1971) that the males of Anisota
virginiensis and A. senatoria may be wasp or bee mimics. The day-flying
males, when gathered in numbers over caged virgin females of their species,
gave the impression of swarming bees. Whether or not this is mimicry has not
been determined.
The possibility of Mullerian (see Glossary) mimicry by Hemileuca maia
maia and H. nevadensis has been suggested (Ferguson 1971; Tuskes et al. 1996)
because of their similarity where their ranges overlap.
An example that may be allopatric Mullerian mimicry occurs between
Dryocampa rubicunda and the Neotropical Royal Moth Psilopygida
apollkinairei, not closely related, but very similar in appearance. Within the
range of D. rubicunda, the notodontid moth Hyparpax aurora is nearly identical .
The noctuid Schinia florida is similar, but with the colors reversed.
Primrose Moth {Schinia florida). Family
Noctuidae, Lake County, Indiana.
Pink Prominent Moth male {Hyparpax
aurora ), Family Nolotontidae, Cook County.
10
Mimicry • Rearing Saturniids
Primrose Moth, Family Noctuidae,
Iroquois County.
Rearing Saturniids
The rearing of saturniids can be a rewarding educational experience. Much will
be learned of the behavior and development of these magnificent insects.
Fortunately, the species occur throughout the state, and none are listed as
endangered or threatened. Breeding stock can be obtained by various means.
Some species overwinter in cocoons that are conspicuous on bushes and trees
during the winter. The easiest cocoons to find containing live pupae are those of
the Cecropia Moth, the Promethea Moth, and the Polyphemus Moth. Overwin¬
tering pupae of other species, whether within a silken cocoon in the leaf litter
below the larval host plant or buried in the soil without a cocoon, are more
difficult to find. Such species are best obtained by collecting adults near a light
at night during the summer months. A female moth collected at a light is almost
certainly mated, and will lay viable fertilized eggs over several days. She
should be placed in a paper bag or other receptacle. No plants are needed; the
eggs will be attached to the paper bag. A female moth obtained from an
overwintered cocoon presents a problem in that it must first mate before
ovipositing, and if the resulting larvae are to be reared, emergence of the female
moth must be synchronized with the spring and summer growth of the larval
food plant. Keeping the cocoons outdoors in a protected place will ensure that
development from pupa to adult occurs at the natural seasonal time for the
species. Most species will mate under captive conditions by placing the two
sexes in a screened cage or porch.
Larvae can be found by carefully searching the foliage of food plants. Look
for feeding damage and for the large fecal droppings on the ground below the
larva. To rear larvae, care must be taken to provide fresh food at all times. The
stress caused by leaves of poor quality or the absence of food for too long will
weaken the larvae and lead to disease. It is important that the larvae not be
crowded. The best results are obtained by confining larvae in a net placed over
an entire bush or tree, if not too large, or over a branch with abundant foliage.
The fabric used for window screens in tents is suitable and will last for several
11
Field Guide to Silkmoths of Illinois
years. The quantity of foliage needed by satumiid larvae is easy to underesti¬
mate. For example, an average-sized lilac bush will support less than 10,
perhaps only 5, cecropia larvae to maturity. In addition to diseases, predators
such as predaceous stink bugs and some carabid ground beetles will cause
losses. Mice can also be a problem, tearing the netting to enter and then feeding
at will on the larvae. Without protection, birds are apt to take all of the larvae.
For more detailed information on rearing, we recommend referring to the
literature cited in the Additional Reading section.
Photographing Insects
Successful photography of insects in nature requires proper equipment, and
equally important, knowledge of the behavior of the insect and its probable
reaction to the approach of the photographer and even the appearance of the
equipment used. A single-lens reflex (SLR) camera will give the best results.
The need for a large image of a small object (the insect) requires the use of a
macro lens (one designed for close focus). For extremely small insects, special
lenses and other devices may be needed for magnification; these will not be
covered here. The reader is referred to texts covering this topic (see “Photogra¬
phy,” page 90). But for those insects over a few millimeters in length, a lens
system that will give up to a twice life-size image, or smaller in most cases, will
be adequate. Most insects require an image ratio of 1 : 1 or less on the film. The
longer the focal length of the lens, the less close the camera needs to be for a
specific size of the image on the film. At the same time, the need for a tripod
increases with the use of a longer focal length lens. For most insects, a tripod
will be a handicap because of the loss of the photographer’s mobility. Rela¬
tively few insects will be found sitting still, due either to air movement or to
active motion by the insect itself. Very few insects will remain in place while
the photographer sets up the tripod and camera. Very often it is necessary to
follow the insect’s image in the viewfinder by moving the camera as the insect
moves. All of this means that either very sensitive film (high ASA/ISO) and an
extremely rapid shutter speed must be used, or that electronic flash is used as the
light source. With flash, slow film can be used (ASA/ISO 25 to 64) and yet
allow the use of the smallest f-stops (f-16 or 22 usually), thus achieving the
maximum possible depth of field and at the same time the best resolution
because of the fine grain of the film. In addition, the extremely short duration of
exposure with electronic flash (1/1000 second or less) stops motion of the
subject, eliminating blurred images.
Exposure by flash has a disadvantage in that the background, if too far
away, will be black. Thus, a flash-illuminated photograph may be less aestheti¬
cally pleasing than one taken under natural lighting.
Problems inherent with the photography of insects are due to insect behavior
in response to the close presence of the photographer and his or her equipment.
Many insects will be easily frightened and take evasive action. A quiet, slow,
12
Photographing Insects
and stealthy approach is needed. The insect compound eye is superbly struc¬
tured to discern movement. A slow approach lessens the chance of a reaction,
that is, flight. No sudden moves should be made. Do not cast a moving shadow
over the insect. Do not jingle keys or chains; the ultrasound produced may
cause sudden flight. Not every insect will permit a close approach, but with
patience some will be discovered that will. The photographer will then do best
by taking a series of pictures. This increases the chances for a really good
photograph. Remember that the cost of film is the least expensive part of the
endeavor.
Insects that are most easily approached without sudden alarm are those that
are feeding, whether on nectar from a flower, the juice from a fermenting apple,
or the liquid on dung or carrion. Often an insect that has recently molted (more
correctly — undergone ecdysis) will remain quiet even when disturbed. If the
temperature is low, many insects will be less apt to take flight. The time of day
may influence behavior, perhaps lessening the tendency to take flight.
Sometimes it may be necessary to first capture the insect, then anesthetize it
by chemical or physical means. For some species, this may be the only way to
get a picture. Chilling in a refrigerator is the safest and is tolerated by most
species. To obtain a lifelike and natural-appearing image, the insect must be
allowed to fully recover so that all appendages and the body will be in a natural
position. Too many pictures have been published with raised tarsi projecting in
the air. Once the insect has recovered, one or more pictures are usually possible.
Chilling is especially productive with nocturnal insects, which can then be
photographed the next day. In these cases, the chilled insect can be placed in a
suitable site and photographed when it has recovered from the cold. Such
insects generally remain quiet for extended periods.
Large insects, such as the nocturnal satumiids, when found during daylight
hours, often (but not always) cannot fly without first increasing their body
temperature to make flight possible. They do this by a quivering action of the
thoracic muscles. During this warm-up there is ample time to obtain photo¬
graphs without difficulty. Using this procedure, most of the photographs in
nature of the satumiids in this book were taken of captive-reared insects.
13
Field Guide to Silkmoths of Illinois
Saturniid Relatives
Female Apatalodes torrefacta Male Apatalodes torrefacta
(Apatelodinae), Cook County. (Apatelodinae), Cook County.
Female Twin-spotted Sphinx Moth, Male White-line Sphinx Moth, Hyles
Smerinthus jamaicensis (Sphingidae), lineata (Sphingidae), Champaign County.
Peoria County.
14
Regal Moth
Regal Moth or Royal Walnut Moth Subfamily: Ceratocampinae
Citheronia regalis (Fabricius, 1793)
Note: The larvae are called Hickory Horned Devils because of their threatening
appearance, although they are harmless.
Description of Adult: Wingspan 95-155 mm (3 3/4-6 1/8 in.). Females are
larger than males. Sexes similar in color. In shape the wings are more elongate
than those of our other satumiids. The body, especially the abdomen, is very
stout. On the upperside, the forewing is olive-gray with veins lined with reddish
brown scales. There are two basal and one discal yellow spots and a yellow-
spotted postmedial band. The hindwing is reddish brown with a yellow anterior
area, and distal patches of olive-gray. The body is reddish brown with yellow
thoracic spots and circular bands between abdominal segments. On the under¬
side the wings are yellow basally, and olive-gray with reddish brown veins on
the distal areas. Yellow postmedial spots are present. At rest, the wings are
flexed, held in a rooflike position over and along the sides of the abdomen
(covered in “Classification” section).
Similar Species: None in Illinois.
Description of Larva: Up to 130 mm (5 1/4 in.) long, the largest caterpillar of
our area. There are five instars; one and two are brown with long conspicuous
spiny thoracic scoli, and shorter scoli on the abdominal segments. Instars three,
four, and five are green, with short abdominal scoli. The thoracic scoli are stout
and spiny, red with black tips. Those on the meso- and metathoracic segments
are the longest. The thoracic legs are red; the abdominal prolegs are black and
green. Each abdominal segment has a diagonal white bar with a black upper
edge, shading into a dark brown area.
Description of Pupae: Pupae are smooth, with a stout cremaster. The species
does not spin a cocoon; mature larvae dig down into the soil and form a cell
within which to pupate. Pupae tunnel their way to the surface for eclosion of the
adult by means of strong abdominal thrusts. In color they are like many moth
pupae, that is, dark brown.
Habitat: Forests, woods, suburban areas, along roadsides where the larval food
plants grow.
Natural History: Univoltine, although there are reports of a second generation
in Missouri. Adults appear during the summer in Illinois. They often come to
light, as do other royal moths. They do not feed, nor do they drink. The
17
Field Guide to Silkmoths of Illinois
mouthparts, as is true of all satumiids, are nonfunctional. Old reports in the
literature of feeding by Citheronia must be due to misidentification. Mating is
nocturnal, in the hours before and after midnight. As with all satumiids, females
release a pheromone creating an odor trail to their location that males can
follow. Eggs are laid in small groups or singly. Upon hatching, the larvae
disperse. The first two instars rest in a curled position, somewhat resembling a
bird dropping. The later instars are green and brown and cryptic. When
attacked, they attempt to defend themselves by violent movements of the head
and thorax, swinging the elongate scoli from side to side. Larvae are polypha-
gous, found usually on hickories ( Carya spp.), persimmon ( Diospyros
virginiana), sumac (Rhus spp.), sweet gum (Liquidambar styraciflua), and
walnuts (Juglans spp.). Larvae can be found on other plant species occasion¬
ally, for example, cotton in the south.
Status: Common in the southern part of the state. Absent or scarce in the
northern and west-central counties. In 50 years of collecting and observation,
JGS has seen only one example in Urbana; it was by a light over an entrance to
the Illini Union on the campus of the University of Illinois, Urbana-Champaign.
In Pope County in southern Illinois, the species was (and is) common at light.
C. regalis ranges from Massachusetts west through the Ohio River Valley, from
south of Chicago to Oklahoma and eastern Texas, east to Llorida and north to
Massachusetts. It is common over much of this range, although disappearing in
the northeast. It is normally found in heavily forested areas.
Reared Hickory Homed Devil (Regal
Moth larva), early instar, Pope
County.
Reared Hickory Horned Devil (Regal
Moth larva), 5th instar, Pope County.
18
Regal Moth
Reared male Regal Moth, Pope County.
Reared female Regal Moth, Pope County.
19
Field Guide to Silkmoths of Illinois
Reared Regal Moth, Pope County.
Reared male Regal Moth, Pope County.
20
Regal Moth
Reared male Regal Moth, Pope County.
Reared male Regal Moth, Pope County.
iegal Moth or
ioyal Walnut Moth
Zither onia regalis
3 published records
■ unpublished records in the
INHS Insect Collection
I sight records by
Bouseman and
Stemburg
I Illinois State
Museum
records
21
Field Guide to Silkmoths of Illinois
Pine-devil Moth Subfamily: Ceratocampinae
Citheronia sepulchralis Grote and Robertson, 1865
Note: The species is not a regular part of the Illinois fauna but has been
collected in the state. We therefore include it in this guide book.
Description of Adult: Wingspan 70-100 mm (2 3/4-5 in.). Males much
smaller than females. Sexes colored alike. Upperside of forewing olive-gray
with faint rosy scales along the veins and a rosy spot at the wing base. A weak
postmedial band is present without yellow spots. Basal region of the hindwing
is rose colored; the outer regions are olive-brown with veins rosy. The body is
entirely brown. On the underside, the wings are rosy.
Similar Species: None in Illinois.
Description of Larva: Length to 100 mm (4 in.). Brown with black shading
not as colorful as C. regalis. The thoracic horns are yellow and shorter, a single
pair on the second and on the third thoracic dorsum. Segments eight and nine of
the abdomen each have a single dorsal scolus.
Description of Pupa: Similar to Regal Moth.
Habitat: Restricted to pine forests.
Natural History: A univoltine
species. Sexes colored alike, but
females may be twice the size of the
males. The larvae feed only on
pines, including Pinus virginiana, P.
rigida, and P. strobus. These pines
have been extensively planted in
Illinois. The life history of the
species does not differ significantly
from that of C. regalis.
Status: Known only as a rare
vagrant in Illinois. The species is
locally common fp the Atlantic
states, from New England to
Florida. It extends into eastern
Ohio, Kentucky, and Tennessee, and
could conceivably reach Illinois.
Pine-devil Moth
Citheronia sepulchralis
53 published records
H unpublished records in the
INHS Insect Collection
I sight records by
Bouseman and
Stemburg
Illinois State
Museum
records
22
Pine-devil Moth
Male Pine-devil Moth, Buncombe County, NC.
Female Pine-devil Moth.
23
Field Guide to Silkmoths of Illinois
Imperial Moth Subfamily: Ceratocampinae
Eacles imperialis (Drury, 1773)
Description: Wingspan 90-165 mm (3 1/2-6 1/2 in.). Sexually dimorphic,
females mostly yellow, males with conspicuous magenta patches. Upperside
yellow with magenta or purple-brown markings. The dark markings are variable
in extent on the forewing submargin and the basal forewing and hindwing
regions. A dark postmedial line crosses both wings; on the forewing it extends
diagonally to the apex. Both wings have small circular gray-centered eyespots
and a scattering of magenta dots. The body is yellow with magenta cross-bands.
On the underside, both wings are yellow, with the eyespots magenta, and
magenta patches reduced or absent.
Similar Species: None in Illinois. Related species occur in Arizona and south
into the Neotropics. A northern subspecies of E. imperialis is found in upper
Michigan and Ontario.
Description of Larva: Length of mature larvae may reach 115 mm (4 1/2 in.).
Color may be green, brown, or black. Long hairlike setae are tan or white. The
spiracles are white with dark blue edges. Meso- and metathoracic dorsal horns
(scoli) are stout and spiny. Small scoli are present on the abdominal segments.
The early instars have the scoli disproportionately long. Larvae are present from
July through September.
Description of Pupa: The rather spinose brown pupa has a bifurcate cremaster.
If disturbed, the abdomen moves in a violent twirling motion. The pupa
overwinters in a cell formed by the larva before pupation; there is no cocoon.
Habitat: Forests, suburban areas, parks, roadsides. The wide variety of trees
and shrubs that serve as larval hosts ensure wide distribution.
Natural History: Univoltine with a long extended emergence; adults present
from June into August. Pupae are the overwintering stage. Adult emergence
takes place near dawn, after which individuals remain quiet until dusk, at which
time they become active. Both sexes are nocturnal. Males are strong fliers,
soon finding females by following the odor trail of the sex pheromone released
by a female, usually during the early morning hours after midnight. Eggs are
laid singly or in small groups on foliage of larval hosts. The species is very
polyphagous, larvae accepting many broad-leaved plants and even some
conifers. A partial list includes birches ( Betula spp.), maples {Acer spp.), oaks
( Quercus spp.), pines ( Pinus spp.), sassafras ( Sassafras albidum), walnuts
(fug Ians spp.), and many others. Larvae disperse to feed and remain solitary
throughout larval life.
24
Imperial Moth
Status: Common statewide. The species comes readily to light and is often
seen at night. It ranges from Massachusetts to Iowa, south to Texas, and east to
Florida and the Atlantic coast, and is often common, a denizen of deciduous
forests and even urban areas.
Reared male Imperial Moth, Champaign County.
Reared female Imperial Moth, Champaign County.
25
Field Guide to Silkmoths of Illinois
Reared Imperial Moth, Champaign County.
Reared Imperial Moth, Champaign County.
Reared Imperial Moth larva (5th instar, Reared Imperial Moth larva (5th instar,
brown form), Champaign County. green form), Champaign County.
26
Imperial Moth
Reared Imperial Moth, Champaign County.
Reared Imperial Moth, Champaign County.
Imperial Moth
Eacles imperialis
£3 published records
Si unpublished records in the
INHS Insect Collection
■ sight records by
Bouseman and
Stemburg
■ Illinois State
Museum
records
Imperial Moth pupa
collected in 1932,
Champaign County.
27
Field Guide to Silkmoths of Illinois
Spiny Oakworm Moth Subfamily: Ceratocampinae
Anisota stigma (Fabricius, 1775)
Description of Adult: Wingspan 40-70 mm (1 5/8-2 3/4 in.). Sexual dimor¬
phism is not pronounced. Males are small and have the wings less rounded.
The general color is bright orange-brown tinged with pink, and densely spotted
with brown. The marginal area beyond the postmedial line has a purplish or
pink cast in both sexes. The fore wing has a round white discal spot, typical of
Anisota spp. A postmedial line crosses the hindwing. At rest the wings are
flexed.
Similar Species: Females of A. senatoria have less dense spots. Females of A.
virginiensis do not have the forewings spotted with dark dots. Males of A.
senatoria and virginiensis are smaller and hyaline, and diurnal, unlike the males
of A. stigma, which are both nocturnal and diurnal.
Description of Larva: Larvae are called Spiny Oakworms. Length to 35 mm
(1 3/4 in.). Head is orange-brown. The body is variable, from red to pink or
brown, with a dense scattering of white granules. The second thoracic segment
has a pair of long spiny horns. Dorsal and lateral short spinulose horns along the
back and sides recurve backwards or downwards. There often is an indistinct
spiracular stripe. Early instars are gregarious, the later instars solitary. These
pupate in the ground. There is one generation in the north, two in the south.
Larvae feed mainly on oak ( Quercus spp.) and occasionally on hazel ( Corylus
spp.).
Description of Pupa: Typical of Ceratocampinae. Pupa with bifurcate
cremaster. Body surface of thorax and abdomen spinose. Pupation in the
ground with no cocoon.
Habitat: Forests and woodlots where there are oaks. Suburban areas, savannas.
Life History: Univoltine. Collecting at night with lights indicates that both
sexes are nocturnal, but daytime observation reveals that males are also diurnal,
actively searching for and mating with females even in broad daylight. Females
lay their eggs after dark on oak leaves, the eggs in groups of 5 to 20 or so. Adult
flight is spread over a long season in June and July, although the life span of any
one individual is only 7-10 days.
Status: Uncommon, but widespread.
28
Spiny Oakworm Moth
Male Spiny Oakworm Moth, Cook County.
Spiny Oakworm early instar larva. Photo
by Phil Nixon.
Female Spiny Oakworm Moth, Cook County.
Spiny Oakworm larva (late instar), Pope
County.
Spiny Oakworm Moth
Anisota stigma
£3 published records
■ unpublished records in the
INHS Insect Collection
■ sight records by
Bouseman and
Stemburg
■ Illinois State
Museum
records
29
Field Guide to Silkmoths of Illinois
Pink-striped Oakworm Moth Subfamily: Ceratocampinae
Anisota virginiensis (Drury, 1773)
Description of Adult: Wingspan of male 40-45 mm (1 9/16-1 3/4 in.), of
female 50-65 mm (2-3 1/2 in.). Sexually dimorphic, females much larger than
males. In the male the forewing has a well-developed hyaline area and dark
brown borders. Its hindwing is dark with a weak postmedial line. The female
has a well-developed postmedial line on both wings with purplish cast in the
area beyond the lines. Both sexes have a well-developed white discal spot on
each forewing. The wings do not have a scattering of dark brown spots. Adults
have reduced mouthparts and neither feed nor drink.
Similar Species: Syssphinx bicolor and S. bisecta lack the hindwing postmedial
line. Anisota stigma, A. senatoria, and S. bicolor have small dark spots on the
wings.
Description of Larva: Length to 55 mm (2 3/8 in.). Known as the Pink-striped
Oakworm. The head is orange-brown and the body is pale olive green, covered
with white granules. The lateral areas are pink. On the mesothorax there is a
pair of dorsal scoli, 6-8 mm long. The spiracles are black with white edges.
Running the length of the body are wide subdorsal and spiracular white stripes.
Description of Pupa: Typical of Ceratocampinae. Pupa with bifurcate
cremaster. Body surface of thorax and abdomen spinose. Pupation in the
ground with no cocoon.
Habitat: Forests, savannas, and suburban areas where there are oaks ( Quercus
spp.).
Life History: Bivoltine. Adults in May and again in July to September. The
species overwinters as pupae in the soil. Males are diurnal, with mating activity
in mid to late morning. The males are fast and erratic fliers, but, when circling
over a cage containing a virgin female, each resembles quite convincingly a
wasp or bee. If the female is free within the cage and the male can enter, mating
takes place at once. There is no courtship; this behavior is common to all of our
satumiids. The pair stays together until dusk, when they separate and egg laying
begins. Eggs are laid on oak leaves in groups of 100 or less. Larvae feed on the
oak foliage, the early instars in groups, later instars separately.
Status: Statewide, often common. Occasional outbreaks cause considerable
defoliation of infested trees.
30
Pink-striped Oakworm Moth
Male Pink-striped Oakworm Moth, Cook
County.
Pink-striped Oakworm Moth, Wayne
County, MO.
Female Pink-striped Oakworm Moth, Cook
County.
Pink-striped Oakworm Moth, Wayne
County, MO.
Pink-striped Oakworm larva. Photo by
James Appleby.
Pink-striped Oakworm Moth
Anisota virginiensis
E9 published records
unpublished records in the
INHS Insect Collection
sight records by
Bouseman and
Stemburg
Illinois State
Museum
records
31
Field Guide to Silkmoths of Illinois
Orange-striped Oakworm Moth Subfamily: Ceratocampinae
Anisota senatoria (J.E. Smith, 1797)
Description of Adult: Sexually dimorphic. Forewing of male is narrow with a
translucent spot. Male wingspan 33^4 mm (1 1/4-1 3/4 in.). Female wingspan
50-65 mm (2-2 1/2 in.). Female has broad, opaque, rounded wings covered
with small spots. In color males are reddish brown in the scaled areas; females
are yellow-brown or reddish brown with pink shading beyond the postmedial
line. Typical of Anisota spp., the forewing has a conspicuous white discal spot.
Males are diurnal; females fly at night, but of course release pheromone to
attract males during the day when mating occurs. Oviposition begins before dark
and continues into the night.
Similar Species: Males of A. virginiensis have large transparent areas, while
females lack spotting. Females of A. stigma are densely spotted and paler.
Description of Larva: The larva is known as the Orange-striped Oakworm.
The body is black, as is the head. Eight (four on each half) light or yellow
longitudinal stripes run the length of the body. There are two rows of black
dorsal scoli and each side has one subdorsal row, all short except for the long
pair on the mesothorax. Larvae are gregarious in the early instars, then dispers¬
ing, but often remaining close together. They feed on oaks and are periodically
a major pest, causing serious defoliation of forest trees.
Description of Pupa: Typical of Ceratocampinae. Pupa with bifurcate
cremaster. Body surface of thorax and abdomen spinose. Pupation in the
ground with no cocoon.
Habitat: Forests where there are oaks ( Quercus spp.).
Life History: Univoltine. Overwinters as pupae in the soil. Adults fly in late
June and July. Males are diurnal, searching for females in late morning, when
mating takes place. The pair separates in the late afternoon, after which the
female begins to oviposit on oak foliage, continuing after dark. Larvae feed
from late July into October.
Status: The species is uncommon, but occasional outbreaks cause serious
damage to oaks. It is one of the few satumiids to attain pest status. The species
ranges from Vermont to Minnesota to Texas and northern Georgia.
32
Orange-striped Oakworm Moth
Male Orange-striped Oakworm Moth,
Cook County.
• ;v
t 't
tw X X 4 Pf
*i±! ^ ....
ss.
m
Female Orange-striped Oakworm Moth,
Cook County.
Orange-striped Oakworm larva. Photo by
James Appleby.
( )range-5triped ( Xikworm \ lotli
Anisota sanatoria
EZ? published records
a unpublished records in the
INHS Insect Collection
sight records by
Bouseman and
Stemburg
Illinois State
Museum
records
33
Field Guide to Silkmoths of Illinois
Rosy Maple Moth Subfamily: Ceratocampinae
Dryocampa rubicunda (Fabricius, 1793)
Description of Adult: Wingspan 35-52 mm (1 3/8-2 1/8 in.). Wings on the
upperside yellow to white with the basal area of the forewing and the outer
margin bright pink. There may be a postmedial band of pink on the hindwing.
The intensity of the pink varies from bright to very pale. The body is yellow.
Some specimens are almost all white, with only a trace of pink.
Similar Species: Hyparpax aurora (J.E. Smith), the Pink Prominent Moth,
family Notodontidae, is remarkably similar in its coloring but has a pink body.
The noctuid Schinia florida (Guerin), the Primrose Moth, is similar except that
the pink pattern differs. It has been suggested (Ferguson 1972, p. 1 1) that this
may be a mimicry complex, with the Rosy Maple Moth the model. We know of
no data proving this supposition, although it is certainly possible.
Description of Larva: The larva is known as the Green-striped Mapleworm.
Full grown to 60 mm (2 3/8 in.). The last larval instar is pale green with seven
longitudinal dark green stripes. The lateral areas of the seventh and eighth
abdominal segments are pink to red. The mesothorax has a single pair of long
black dorsal scoli. Short black hornlike lateral scoli are present from the
mesothorax to the eighth abdominal segment. There is a pair of mid-dorsal scoli
on the ninth abdominal segment. The entire body is covered with rounded
granules. The head is orange-brown.
Description of Pupa: Typical of Ceratocampinae. Pupa with bifurcate
cremaster. Body surface of thorax and abdomen spinose. Pupation in the
ground with no cocoon.
Habitat: Forests where the larval hosts occur. Maples {Acer spp.), especially
red (A. rubrum), silver (A. saccharinum), and sugar maples (A. saccharum), and
sometimes oaks {Quercus spp.) are the food plants favored.
Natural History: Populations are univoltine in the north, multivoltine in the
south where there can be three generations. Pupae of the last generation
overwinter in cells in the soil made by the last generation larvae. First genera¬
tion adults appear in May. They come to light readily and are nocturnal, resting
quietly during daylight hours. Like all satumiids the adults neither feed nor
drink, and depend for energy entirely on the reserves stored during the larval
stages. Adults survive for 1 week to 10 days. First instars are gregarious; later
instars are solitary.
34
Rosy Maple Moth
Status: Usually common, sometimes abundant. It can be found statewide.
Remarks: At rest, the Rosy Maple Moth holds its wings in a flexed position
over and against the sides and upper surface of the abdomen.
Male Rosy Maple Moth (light form), Cook
County.
Green- striped Maple Worm (late instar).
Photo by Phil Nixon.
Rosy Maple Moth (light form), Wayne
County, MO.
Rosy Maple Moth (pink form), Wayne
County, MO.
Male Rosy Maple Moth (pink form), North
Carolina.
Male Rosy Maple Moth (pink form),
Champaign County.
Rosy Maple Moth
Dryocampa mbiauida
E2 published records
81 unpublished records in the
INHS Insect Collection
Hi sight records by
Bouseman and
Stemburg
■ Illinois State
Museum
records
35
Field Guide to Silkmoths of Illinois
Bisected Honey Locust Moth Subfamily: Ceratocampinae
Syssphinx bisecta (Lintner, 1879)
Description of Adult: Wingspan 55-75 mm (2 1/8-3 in.). Sexes similar, with
males smaller. General color varies from yellowish to orange. A reddish area of
the hindwing varies in size. The variations are not seasonal, but occur in each
generation. The forewings of females are stippled with dark spots, usually
absent in males. A thin, black postmedial line runs from the forewing apex to
the base of the inner margin, bisecting the forewing.
Similar Species: None. The thin black postmedial line is diagnostic for S.
bisecta.
Description of Larva: Length to 50 mm (2 in.). Body green with silvery white
granules. Second and third thoracic segments each with one pair of long orange
to blue hornlike scoli. The caudal horn is yellow at its base, red to black
towards the tip. Conspicuous abdominal tubercles are conical and sharp, shiny
white, and directed upward and backward. The spiracular stripe is blue above
and yellow below.
Description of Pupa: Typical of the royal moths, spinulose, with a prominent
cremaster. Pupation is in the soil, with no cocoon.
Habitat: Forests where there are honey locusts and/or Kentucky coffee trees.
Life History: Overwinters as a pupa without a cocoon in the soil. The species
is bivoltine in the Midwest, with adults in May and July. Emergence of first
generation adults is in May, the second generation appearing in July. There is
apparently little if any seasonal dimorphism. Emergence is in the late afternoon,
with mating occurring trom late evening to early morning. The female begins
oviposition the next night on honey locust ( Gleditsia triacanthos) and Kentucky
coffee tree ( Gymnocladus dioicus). S. bisecta and S. bicolor are sympatric and
active at the same time. Hybridization is apparently prevented by differences in
the pheromones released by the females.
Status: Not uncommon. Probably statewide, but usually less common than S.
bicolor.
Remarks: The generic name Sphingicampa is used by some authorities.
36
Bisected Honey Locust Moth
Male Bisected Honey Locust Moth,
Champaign County.
Female Bisected Honey Locust Moth,
Peoria County.
Male Bisected Honey Locust Moth,
Champaign County.
Bisected Honey Locust Moth larva. Photo
by James Appleby.
Bisected Honey Locust Moth
Syssphinx bisecta
S3 published records
M unpublished records in the
INHS Insect Collection
■ sight records by
Bouseman and
Stemburg
■ Illinois State
Museum
records
37
Field Guide to Silkmoths of Illinois
Honey Locust Moth Subfamily: Ceratocampinae
Syssphinx bicolor (Harris, 1841)
Description of Adult: Wingspan 45-65 mm (1 7/8-2 5/8 in.). Sexually
dimorphic, seasonally polymorphic. Males are much smaller than the females
and have less-rounded wings. In all seasonal forms the forewings are colored
for concealment; the hindwings are colored with red that is revealed when the
moth is disturbed (see photographs, page 40). Forewings of the spring brood are
gray, yellow-orange in the summer brood, and brown in the third brood. An
indistinct postmedial line reaches the forewing costa before the apex. A light to
heavy dusting with brown spots occurs on the forewings. The white discal spot
of the forewing may be double, single, or absent.
Similar Species: Anisota spp. lack a red patch on the hindwings, which have a
distinct postmedial line. Syssphinx bisecta has the postmedial line of the
forewing extended to its apex.
Description of Larva: Length to 55 mm (2 1/8 in.). The body is green with a
bluish cast. The lower side of the abdomen bears scattered silvery white and
black granules. There is a spiracular abdominal line, reddish purple above and
white below. The second and third thoracic segments both have a pair of
hornlike scoli, rose to red in color, and tipped with black. They are recurved in
position. The abdominal segments have a variable number of short dorsal and
subdorsal horns, silver and bright pink in color. There is a prominent mid-dorsal
silver and coral-red horn on the dorsum of the eighth abdominal segment.
Habitat: Forests where there are honey locusts and/or Kentucky coffee trees.
Description of Pupa: Typical of the subfamily, spinose with a well-developed
cremaster.
Life History: Pupae of the last generation overwinter in cellular cavities formed in
the ground by larvae. Emergence of the first brood of adults is in May. Their
larvae (and all subsequent larvae) feed on the leaves of honey locust ( Gleditsia
triacanthos ) and Kentucky coffee tree ( Gymnocladus dioicus ), then pupate in the
soil. Second-brood adults are found in midsummer, July and August; third brood,
if present, appears in September. Adult emergence occurs in the evening, followed
by mating that night. The next evening the pair separate and the female begins
oviposition that night. The male will mate again if it can find another female. The
female mates only once. Eggs are laid singly or in small groups on leaves of the
host plant. Hatching occurs within five days or more. Larvae develop rapidly,
becoming full grown within three weeks. The pupal stage in the ground lasts two
weeks, except for the overwintering pupae that have entered diapause.
38
Honey Locust Moth
Status: Common to scarce, depending on local conditions. Statewide.
Remarks: The generic name Sphingicampa is used by some authorities.
Female Honey Locust Moth (spring form),
Male Honey Locust Moth (spring form), Champaign County.
Champaign County.
Male Honey Locust Moth (summer form), Female Honey Locust Moth (summer
Champaign County. form), Champaign County.
Honey Locust Moth larva (5th instar),
Champaign County.
Honey Locust Moth (resting position,
spring form), Champaign County.
39
Honey Locust Moth (resting position,
summer form), Champaign County.
Field Guide to Silkmoths of Illinois
Honey Locust Moth (defensive display,
summer form), Champaign County.
Honey Locust Moth (defensive display,
spring form), Champaign County.
Honey Locust Moth
Syssphinx bicolor
E3 published records
■ unpublished records in the
INHS Insect Collection
■ sight records by
Bouseman and
Stemburg
■ Illinois State
Museum
records
40
Buck Moth
Southern Illinois Population
Hemileuca maia maia (Drury, 1773)
Subfamily: Hemileucinae
Description of Adult: Wingspan 50-75 mm (2-3 in.). Sexes similar, except
the abdomen is entirely black in the female and males have the tip of the
abdomen bright red. Both wings are black, each crossed by a white medial band
with a black discal spot that touches the black basal area. The undersides of the
wings are much like the uppersides. Male antennae are bipectinate with long
rami almost to their tip. Female antennae are bipectinate with short rami.
Similar Species: H. nevadensis of the Great Lakes complex. See discussion
under that species.
Description of Larvae: Length to 60 mm (2 3/8 in.). The color varies from
off-white to black, dusted with yellow specks. There may be an indistinct white
spiracular stripe. The body is covered with dense tufts of urticating spines, a
deterrent against predators. Handle with care! The toxic substance released by
the spines may cause a burning sensation or even swelling. Larvae feed on oaks
( Quercus spp.). There are six larval instars.
Description of Pupa: Typical of Hemileuca spp., there is a short simple
cremaster with hooks. The abdominal segments do not telescope and the body is
without exposed spines. The pupa is enclosed in a cocoon beneath leaf litter,
where it is spun by the larva.
Habitat: Oak forests.
Life History: Univoltine. Overwinters as masses of eggs encircling twigs of
the larval host, or sometimes on adjacent nonhost plants. Eggs are laid in late
October. After the oaks leaf out in the spring, the eggs hatch. The first few
instars remain together, feeding on the leaves; later instars tend to disperse, and
during this movement may wander onto plants that are not fed upon. Because of
this, reports of feeding on a variety of plant species that are not food plants may
be in error. One that does appear to be correct is hazel ( Corylus spp.). Larvae
pupate on or in the ground where there is leaf cover in late August and Septem¬
ber. Emergence of adults is in October at the time of leaf fall. Both sexes are
diurnal, with males searching for and mating with the females in bright sunlight
during the late morning and early afternoon hours. On separating, egg-laying
begins that day. Buck Moths are swift fliers, not easily captured. Resting adults
when disturbed often fall to the ground with wings folded together above the
thorax and the abdomen curled and extended so that the red tip (in males) is
41
Field Guide to Silkmoths of Illinois
conspicuous. In this way it increases the aposematic appearance in much the
same manner as the unrelated tiger moths such as the Salt Marsh Caterpillar
Moth. The display lasts a few minutes or until the disturbance is over before the
moth climbs back up a support. There is evidence that some pupae delay
emergence until their second summer.
Status: Local to uncommon in southern Illinois, with a few records from
central Illinois that may not be accurate. Buck Moths resembling H. m. maia
occur in northeast Illinois, but feed only on willows (Salix spp.) or poplar
(. Populus spp.). They are thought to be H. nevadensis , or a hybrid of that species
with H. m. maia.
Male Buck Moth, Hardin County (James
Wiker Collection).
Male Buck Moth, Hardin County (James
Wiker Collection).
Buck Moth larva (late instar), Franklin
County, MA. Photo by James Tuttle.
Female Buck Moth ovipositing, Vinton
County, OH. Photo by James Tuttle.
Buck Moth
Hemileuca maia maia
£3 published records
■ unpublished records in the
INHS Insect Collection
■ sight records by
Bouseman and
Stemburg
■ Illinois State
Museum
records
42
Nevada Buck Moth
Hemileuca nevadensis Stretch, 1872
Subfamily: Hemileucinae
Great Lakes Population: In the northeastern counties of Illinois there is a
population of buck moths that resembles H. maia maia of the eastern and
southern U.S., but whose larvae feed on Salix spp. (willows) and sometimes
Populus spp. (poplars), and not on Quercus ilicifolia (scrub oak) or other oaks.
This willow-feeding population extends from Minnesota through Wisconsin and
Michigan to Illinois, Indiana, and Ohio. In the southern part of this range, from
Illinois to Ohio, the adults are essentially indistinguishable from H. m. maia, and
identifiable in a collection only by their locality labels. From the daik maia-
like” population northward and westward there is a cline leading to a lighter and
more translucent population that merges in Minnesota with typical H.
nevadensis . The latter ranges from Minnesota west to the Pacific Coast, always
feeding on willows and poplars. Through the Great Lakes region, willows are
the usual host, although some local populations are found on bogbean
(Menyanthes trifoliata), dwarf birch (. Betula pumila), and purple loosestrife
C Lythrum salicaria ). Apparently, none are on oak. In Ohio, the Great Lakes
willow-feeding population meets the true oak-feeding H. maia maia. In Illinois
the dark “mm'alike” population survives on willow or poplar. The distribution
of the two taxa suggests hybridization may have occurred, but no data are
available for substantiation. Another possibility is mimicry, perhaps Mullerian,
with the western H. nevadensis evolving a color pattern like that of the apose-
matically colored H. maia maia.
Description of Typical H. nevadensis : Wingspan 50-70 mm (2-2 3/4 in.).
From Minnesota west, typical Nevada Buck Moths have less-intense black basal
and marginal areas than H. m. maia. The white medial area is broader, and the
forewing discal spot does not touch the dark basal region. The wings appear
more translucent than those of H. m. maia. The male has a red-tipped abdomen;
the female has an all-black abdomen.
Description of Illinois H. nevadensis : The adult moths are identical in appear¬
ance with H. m. maia, but differ greatly in choice of larval host plant.
Description of Larvae: Not unlike those of H. m. maia.
Description of Pupae: Similar to H. m. maia.
Habitat: Wetlands where willows grow.
Life History: The species is univoltine. Eggs are laid in bands encircling the
43
Field Guide to Silkmoths of Illinois
twigs of willow (or sometimes a nearby plant). These hatch in the spring after
the willows leaf out. The Nevada Buck Moth of northern Illinois is known to
feed on willow, sometimes on poplar, but not on oak. In late summer they
pupate in silken cocoons in the leaf litter on the ground. Emergence is in
October. Adults are diurnal, mating and ovipositing during bright sunlight. The
dark males behave much like aposematic tiger moths when disturbed, falling to
the ground with wings together above the thorax and the abdomen curled and
extended. This defense is typical of many unpalatable moths.
Status: Because of loss of wetland habitat, the moth is more local in distribu¬
tion, but uncommon to common where it occurs in the northern sector of the
state.
Male Nevada Buck Moth (Great Lakes
population), Hessville, IN.
Female Nevada Buck Moth (Great
Lakes population), Hessville, IN.
Larval aggregation (early instar) with
parasitoid on left, Lucas County, OH.
Photo by James Tuttle.
Male Nevada Buck Moth (typical of
western population), California.
Nevada Buck Moth larva (late instar), Polk
County, MN. Photo by James Tuttle.
Nevada Buck Moth
Hemileuca nevadensis
published records
M unpublished records in the
INHS Insect Collection
® sight records by
Bouseman and
Stemburg
■ Illinois State
Museum
records
44
lo Moth
Automeris io (Fabricius, 1775)
Subfamily: Hemileucinae
Description of Adult: Wingspan 50-85 mm (2-3 1/4 in.). Sexually dimorphic.
Males much smaller than females. On the upperside males are mostly yellow
with scattered brown spots and a weak broken- spotted medial line nearly
parallel with the outer margin of the forewing. In contrast, the forewings of the
female are purplish red to reddish brown instead of yellow and are otherwise
similar. The hindwings of the two sexes are similar, each wing with a black
discal spot with a blue and white center, a reddish brown postmedial band
partially surrounding the eyespot, and a submarginal band beyond, with a yellow
wing margin. The inner margin of the hindwing is red. On the underside the
male is yellow, the postmedial lines are red, and on the hindwing the inner
margin is red. The eyespots are black with white centers. The female is red-
brown instead of yellow on the underside and is otherwise similar to the male.
At rest the wings are held flexed over the abdomen, concealing the hindwing
eyespots. Males have the antennae quadripectinate nearly to the tip; the females
have bipectinate antennae.
Similar Species: None in Illinois. Related species occur in the western United
States and south into the Neotropics.
Description of Larva: Length to 60 mm (2 3/4 in.). Rather stout green body
with dense tufts of green spines, finely branched into urticating (stinging)
spinules. These can cause a painful rash and swelling if touched. Handle with
great care! The spiracles are white. A conspicuous red lateral line is present,
bordered below by white and passing through the spiracles. Thoracic and
abdominal legs are red. There are five larval instars.
Cocoon: The species overwinters as a pupa in a somewhat shapeless but sturdy
cocoon spun among fallen leaves and ground litter.
Habitat: Forests, savannas, woody roadsides, occasionally in cornfields.
Widespread.
Natural History: Univoltine in the north, bivoltine in Illinois. Overwinters as
a pupa in a cocoon on the ground. Emergence is in May, and adults of the
second generation are found throughout the summer. Look for them at night at
lights. The species is extremely polyphagous, the larvae feeding upon most
species of deciduous trees and shrubs, and on coarse grasses including corn ( Zea
mays). They have also been found on clover and other forbs. The list of trees
includes apple ( Malus spp.), basswood ( Tilia spp.), blackberry ( Rubus spp.),
black cherry (. Prunus serotina ), elm ( Ulmus spp.), hackberry ( Celtis spp.),
45
Field Guide to Silkmoths of Illinois
hickory ( Carya spp.), maple ( Acer spp.), oak ( Quercus spp.), poplar ( Populus
spp.), privet (Li gust rum spp.), redbud ( Cercis canadensis), sassafras ( Sassafras
albidum), willow (Salix spp.), and others. First and second instars are gregari¬
ous, brown in color; the later instars are green and solitary. All have stinging
spines.
Status: Usually common, sometimes abundant. Several years ago willows
along Route 150 near Oakwood were almost completely defoliated by this moth.
The species probably occurs in every county in the state. It is widespread
throughout eastern North America. The species ranges from Nova Scotia to
Manitoba, south to Texas and Florida.
Reared male Io Moth, Champaign County.
Reared female Io Moth, Champaign County.
46
Io Moth
Reared male Io Moth (defensive display), Champaign County.
Reared male Io Moth
(resting position),
Champaign County.
Reared female Io Moth,
(resting position)
Champaign County.
Reared female Io Moth (defensive display), Champaign
County.
Io Moth
Automeris io
E published records
ifl unpublished records in the
INHS Insect Collection
■ sight records by
Bouseman and
Stemburg
■ Illinois State
Museum
records
Field Guide to Silkmoths of Illinois
Polyphemus Moth Subfamily: Saturniinae
Antheraea polyphemus (Cramer, 1776)
Description: Wingspan 1 10-150 mm (4 1/4-6 in.). Sexes similar, female
forewing apex rounder than in male. General color varies from light brown or
tan to yellowish brown, reddish brown, orange, or even melanic. On the
upperside each wing has a transparent discal eyespot, the largest on the
hindwing. The eyespot of the forewing is narrowly bordered with yellow and
black. On the hindwing the eyespot has a narrow yellow partial border and a
broad asymmetrical black border. The hindwing eyespots give the impression of
a pair of shiny vertebrate eyes. There is a black submarginal line on both wings,
lined outwardly with pink. The forewing has a broken basal dark line, basally
bordered by pink. On the underside the wings have a strong resemblance to a
dead leaf, with a scattering of light tan and dark brown areas. The eyespots are
present, visible as transparent spots, but without the bordering colors that give
the upperside spots a resemblance to vertebrate eyes. Thus, at rest, with the
wings held vertically and together, the moth is cryptic, blending in with dead
leaves. When the moth is first disturbed the wings are held outstretched,
suddenly revealing the upperside eyespots. Known as a flash coloring display,
this may deter some predators, although certainly not the Blue Jays in the
backyard of one of us (JGS). Further disturbance causes the moth to bounce
along the ground by downward thrusts of the forewing and elevating the
hindwings at each bounce. This action further deters some predators that are
frightened off by the staring (although false) eyes. Antennae of the males are
broadly quadripectinate; those of the female are narrowly quadripectinate.
Similar Species: None in Illinois. Related species occur in Asia.
Description of Larva: The five larval instars are all bright green with an
oblique yellow line on each side of abdominal segments two through nine.
Tubercles (scoli) are small and reddish with a metallic iridescence. In silhouette
the larval segments are convex, giving the appearance of a jagged leaf. The last
larval instar is 75 mm (3 in.) or more in length.
Description of Cocoon: The egg-shaped cocoon is spun within leaves on the
larval host plant and fastened in place by silken threads along the leaf stem. The
connection is not strong; many cocoons fall to the ground during or before
wintei. The cocoon is thick-walled, stiff and hard, and has no escape valve. As
with the Luna Moth, the eclosing adult softens the silk, then tears the weakened
threads by means of hard spurs at the bases of the forewings.
Habitat: Forests and urban areas.
48
Polyphemus Moth
Natural History: Bivoltine in Illinois. Adults of the first generation from
overwintered pupae emerge in May and June. Their progeny become adults in
July and August. First-generation adults have wingspans of up to six inches or
more. Second-generation adults are almost always smaller, irrespective of the
plant species consumed by the larvae. Eclosion of the adults is usually in the
afternoon. Mating takes place that night sometime near midnight or later. The
pair stays together until the next evening. Females lay the white and brown eggs
singly or in small groups on the larval host plant. Upon hatching (in 10 days or
so), the larvae disperse to feed. The species is extremely polyphagous; more
than 50 kinds of trees or shrubs serve as hosts. These include apple ( Malus
spp.), birches ( Betula spp.), cherries ( Primus spp.), dogwoods ( Cornus spp.),
elms ( Ulmus spp.), maples {Acer spp.), oaks (Quercus spp.), poplars {Populus
spp.), plums {Prunus spp,), roses {Rosa spp.), walnuts {Juglans spp.), willows
{Salix spp.), and many others. One of us (JGS) once found a large patch of wild
roses in a vacant Chicago lot with over 100 cocoons present.
As is true of all saturniids, the adults do not feed or drink. They survive
only as long as their energy reserves last, usually in less than a week to 10 days.
Females release a pheromone to attract males. A female mates with the first
male to find her and never mates again.
Status: Common statewide. It is often most common in rural areas. The
practice of raking and disposing of leaves in urban areas must cause destruction
of cocoons on the ground. The species thrives along roadsides and in wooded
areas in general. The Polyphemus Moth is found from the Atlantic to the
Pacific, and from Canada into Mexico, and is locally common throughout its
range.
Reared male Polyphemus Moth, Champaign County.
49
Field Guide to Silkmoths of Illinois
Reared female Polyphemus Moth, Champaign County.
Reared male Polyphemus Moth (reddish brown form), Champaign County.
50
Polyphemus Moth
Reared Polyphemus Moth larva (5* instar), Polyphemus Moth recently spun
cocoon,
Champaign County. Champaign County.
Overwintering Polyphemus Moth cocoon,
Champaign County.
Polyphemus Moth pupa,
Champaign County.
Reared male Polyphemus Moth (light-brown form), Champaign County.
51
Field Guide to Silkmoths of Illinois
Reared Male Polyphemus Moth (resting position), Champaign County.
Polyphemus Moth
Antheraea polyphemus
published records
® unpublished records in the
INHS Insect Collection
■ sight records by
Bouseman and
Stemburg
■ Illinois State
Museum
records
52
Luna Moth
Actias luna (Linnaeus, 1758)
Subfamily: Saturniinae
Description: Wingspan 95-135 mm (3 3/4-5 1/4 in.). Sexes similar, although
the hindwing tails of the females tend to be shorter. Seasonally dimorphic; first
generation with wing margins red, second generation with wing margins yellow.
On the upperside, the costal margin of the forewing has a conspicuous broad
brown edging. Fore and hindwings both have a discal eyespot, edged with black
and white with a transparent center. The eyespot of the forewing connects to the
costal band by a red-brown bar. The overall color is pale green, with white, or
very pale yellow body setae. A prominent character is the greatly extended
inner margin of each hindwing forming two long green tails. The undersides of
the wings are pale green, with the eyespots faintly visible.
Similar Species: None in Illinois. Related species are Eurasian.
Description of Larva: All five instars are green with prominent segmentation.
The last instar attains a length of about 75 mm (3 in.). On each side there are a
dorsal and two lateral rows of small red scoli all covered with short setae. A
yellow line passes through the spiracles. There may also be narrow vertical
yellow bands between the abdominal segments. When fully fed, the last (fifth)
instar changes color from green to reddish brown. At this time the gut is
emptied of its contents.
Description of Cocoon: Pupation is within a silk cocoon spun by the fifth
instar. The cocoons are spun among the fallen leaves and other litter on the
ground, where they hide and are protected by the accumulated ground cover. In
spinning its cocoon, the larva first pulls the edges of a leaf together, forming a
shelter within which a thin-walled silken cocoon is formed without an escape
valve. Emergence by the adult is facilitated by its softening of the silk by means
of a regurgitated fluid, after which the weakened silk at the anterior end of the
cocoon is tom apart by means of small sharp thoracic spurs.
Habitat: Forests, although sometimes wooded urban areas when walnuts and
hickories, the principal larval hosts in Illinois, are present.
Natural History: Bivoltine in Illinois. Overwintering pupae complete develop¬
ment as warm temperatures return, emerging as first-generation adults in May
and June. Their progeny become adults in late July and August. A partial third
generation sometimes occurs in the south. The species is polyphagous. Females
lay their eggs singly or in small groups on a variety of larval host plants. In
Illinois hickories ( Carya spp.) and walnuts ( Juglans spp.) are favored. Other
53
Field Guide to Silkmoths of Illinois
hosts include sumacs ( Rhus spp.), persimmon ( Diospyros virginiana), sweet
gum ( Liquidambar styraciflua ), and occasionally others. White birch ( Betula
papyrifera ) is used by more-northern populations.
Luna Moths after emergence remain quiet and inactive until evening, when
flight begins. Mating usually takes place several hours after nightfall, often after
midnight. Once coupled, the pair will remain together until dusk of the follow¬
ing day, unless disturbed earlier. Transfer of sperm is complete within 15
minutes of copulation. Males locate females by flying upwind toward the
source of the odor trail created by a virgin female as she releases the sexual
pheromone. Usually the first male to locate the female mates with her without
any preliminary courtship. Once mated, female satumiids never again release
pheromone; they mate only once. Males, however, can mate each night of their
short life, only a week to 10 days in duration. During this time the females lay
their eggs singly or in groups on the foliage of the larval host plant. The eggs
hatch in about one week. The larvae are not gregarious, but disperse to feed.
Status: Common throughout Illinois. The species occurs in the eastern U.S.
and lower Canada from the eastern Great Plains to the Atlantic Coast and from
Nova Scotia to Florida and Ontario to Texas. It is often the most common wild
silkmoth present.
Remarks: A Luna Moth in flight is an impressive sight, especially if it is seen
during the day when the moth is frightened into flight. The movements of the
wings with the inner margins of the hindwings held close to the abdomen result
in the long trailing tails twisting in a rolling motion against one another, a
motion that adds greatly to the moth’s beauty and charm. The unusual wing
shape and beauty of the Luna Moth have contributed to its popularity with
amateur collectors and naturalists everywhere. Once seen, it is never forgot¬
ten — a truly spectacular insect. The Luna Moth has also been called the Moon
Moth.
Reared Luna Moth cocoon, Champaign
County.
54
Luna Moth
Reared male Luna Moth
(spring form), Champaign
County
Reared male Luna Moth
(summer form),
Champaign County.
55
Field Guide to Silkmoths of Illinois
Reared male Luna Moth (startled), Champaign County.
Reared male Luna Moth (resting position), Champaign County.
56
Luna Moth
Reared female Luna Moth (resting position), Champaign County.
•Aspl
Luna Moth pupa.
Luna Moth
Actias tuna
published records
8:1 unpublished records in the
INHS Insect Collection
SS sight records by
Bouseman and
Stemburg
■ Illinois State
Museum
records
57
Field Guide to Silkmoths of Illinois
Promethea Moth or Spicebush Silkmoth Subfamily: Saturniinae
Callosamia promethea (Drury, 1773)
Description of Adult: Wingspan 75-95 mm (3-3 3/4 in.). Sexually dimorphic.
Male black on the upperside with sinuous postmedial whitish line across both
wings, a small forewing apical eyespot, and a violet apical area. The wing
margins are light buff. An occasional individual may have faint discal spots.
On the underside the basal areas are purplish black with a postmedial separation
from a plum-colored region. Females have the same wing patterns, along with
angular discal spots, but the general color is yellow-brown to red-brown and not
black. The female wings are more rounded than those of the male.
Similar Species: Females of C. angulifera lack the reddish color of C.
promethea females, and have the discal spots larger. Males of C. promethea in
active flight can be mistaken for a dark blackish swallowtail butterfly. Experi¬
mental studies have shown that they are Batesian mimics of the toxic and
unpalatable Pipevine Swallowtail ( Battus philenor) in flight. See discussion
below.
Description of Larva: Length to 75 mm (3 in.). Body is light green with a
slight bluish cast. Second and third thoracic segments bear paired bright red
scoli. There is a single yellow to red scolus on the dorsum of the eighth abdomi¬
nal segment. Other segments bear small black reduced scoli. There is no low
lateral white band, as in C. angulifera larvae.
Description of Pupa and Cocoon: The smooth brown pupa has no cremaster;
it is enclosed within a double-walled cocoon spun by the fifth (last) larval instar
within a rolled leaf, usually of the larva’s host plant. Silk spun by the larva
along the leaf stem and adjacent twig prevents the cocoon from dropping to the
ground. They are therefore easily found hanging from the branches in winter
when the trees are bare.
Habitat: Promethea is most successful where trees are somewhat isolated, as
along fence rows or the edges of fields, in savannas, and in suburban or urban
areas where the trees are not too numerous. As a rule, the species does not do
Reared Promethea Moth larva (5th instar, Reared Promethea Moth larva (5th instar,
side view), Champaign County. dorsal view), Champaign County.
58
Promethea Moth
well in heavily forested sites. Larvae are polyphagous, feeding on many plant
families. In Illinois we have found sassafras ( Sassafras albidum), tulip tree
{Liriodendron tulipifera), and wild black cherry ( Prunus serotina ) to be favored.
Other common larval hosts are ash ( Fraxinm spp.), lilac ( Syringa spp.), maples
(Acer spp.), spicebush ( Lindera spp.), sumac (Rhus spp.), sweet gum (Liquidam-
bar styraciflua), and others.
Life History: In the north, Promethea is univoltine, with adult emergence in
June. In central and southern Illinois the species is bivoltine, with the first
generation appearing in May and early June from overwintered pupae, and the
second-generation adults present in August. In a bivoltine population, pupal
progeny from the first-generation adults do not diapause but develop directly to
the second-generation adults. All the progeny of the second generation enter
pupal diapause, as do a few from the first generation, and must undergo wintei
conditions to develop further.
Male Promethea Moths are diurnal, active from early afternoon to late
afternoon, during which time they actively search for females by following the
odor trails of pheromone released by calling females. Upon successful location
of a female, mating takes place without courtship, at which time the female
ceases to release pheromone. The couple stays together until evening when the
female breaks away and begins oviposition activity. Males aie inactive at night,
they do not come to light. Females, however, sometimes do come to light.
Females do not fly during daylight hours but of course are active in releasing
pheromone at the proper time. As with Satumiidae in general, females mate
only once.
In flight, the black Promethea Moth males resemble black-colored swallow¬
tail butterflies. The flight speed and wing-beat frequency, to our eye, appears
similar, and it is often difficult to recognize that the moth is not a butterfly.
Experimental evidence indicates that the species is a Batesian mimic of the
Pipevine Swallowtail (Battus philenor ), which is known to be unpalatable or
even toxic when eaten by a bird. Laboratory tests have shown that Promethea
Moths are palatable to birds. Males fly from early afternoon to near dusk, much
of this time coincides with the flight activity of Pipevine Swallowtails. In field
tests, male Promethea Moths were painted to resemble either the palatable edible
yellow Tiger Swallowtail (Papilio glaucus ) or the unpalatable Pipevine
Swallowtail. These were released in equal numbers in an area with mature
forest, prairie, and second growth on former agricultural fields. The released
painted male moths were reassembled by attraction to traps baited with virgin
female moths. The results, here briefly summarized from data obtained over
three summers, showed that moths painted to resemble an unpalatable butterfly
survived longer and with less bird damage after release than those painted to
resemble a palatable butterfly. Many of the recaptured yellow-painted moths
(the Tiger Swallowtail mimics) had clear evidence of attack by birds, that is,
beak-shaped tears on the wings. Damage to the black-painted moths (the
Pipevine Swallowtail mimics) was comparatively minimal.
59
Field Guide to Silkmoths of Illinois
Status: Common to uncommon locally. Statewide distribution.
Remarks: One of us (JGS) remembers his first encounter with the diurnal
Promethea males coming to newly emerged female Promethea Moths held
within a screened porch in Chicago, near Evergreen Park. Two females had
eclosed that morning and began to call (release pheromone) that afternoon. The
air became crowded with males seeking females. A conservative estimate of
their numbers was near 50. It was an impressive sight, especially to him at the
age of 14.
Male Promethea Moth, Coles County.
Reared Promethea Moth egg mass,
Champaign County.
Reared Promethea Moth larvae (early
instar), Champaign County.
Reared Promethea Moth
Champaign County.
(3rd
instar),
60
Promethea Moth
Reared female Promethea Moth, Champaign County.
Reared Promethea Moth mated pair
(female upper). Champaign County.
Reared Promethea
Moth cocoon,
Champaign County.
Promethea Moth
pupa, Champaign
County.
61
Reared male Promethea Moth recently emerged on cocoon, Champaign County.
Reared male Promethea Moth (resting postion), Champaign County.
62
Promethea Moth
Reared female Promethea Moth (resting
position), Champaign County.
Promethea Moth
Callosamia promethea
E3 published records
M unpublished records in the
INHS Insect Collection
*1 sight records by
Bouseman and
Stemburg
■ Illinois State
Museum
records
63
Field Guide to Silkmoths of Illinois
Tulip Tree Silkmoth Subfamily: Saturniinae
Callosamia angulifera (Walker, 1885)
Description of Adult: Wingspan 80-1 10 mm (3 1/8-4 3/8 in.). Sexually
dimorphic, males darker than females. Seasonally dimorphic, the summer brood
males darker than those of the spring brood. The two sexes are alike in the
pattern of the markings but differ in coloring. Males are light brown to dark
brown, the females yellow-brown to orange-brown. Both wings are crossed by
an irregularly waved, white postmedial line. Angulate discal spots are present
on the wings, the largest on the forewings. The area basad to the postmedial line
is dark, whereas the area beyond the line is light-shaded. On the underside of
the male the area beyond the postmedial line is light pink, contrasting greatly
with the dark brown basal area. In the female, differences in contrast are similar
to those of the male, but the dark areas are reddish brown.
Similar Species: Females of C. promethea are similar in pattern, but their
general coloring is more reddish to darker brown.
Description of Larva: Length to 70 mm (2 3/4 in.). The body is whitish green
with a white low lateral stripe along the side. The second and third thoracic
segments both have a pair of red dorsal scoli. The eighth abdominal segment
has a single yellow dorsal scolus. Most abdominal segments have a dorsal, a
lateral, and a ventral small black scolus.
Description of Pupa: The pupa is always to be found in a silken cocoon. The
pupa is typical of the Saturniinae — brown, without a distinct cremaster, and
smooth-bodied. The double-walled cocoon is spun within the folds of a leaf, but
not fastened to the leaf stem, so that the cocoon eventually falls to the ground
with leaf drop. The silk is dark, and the cocoon more or less irregularly shaped.
Habitat. This species feeds only on tulip tree foliage {Liriodendron tulipifera )
in nature, and thus is to be found in forested regions where the plant grows.
Natural History: Bivoltine in Illinois. First-generation adults emerge in May
from pupae that have overwintered on the ground within their cocoons. Both
sexes are nocturnal. Mating occurs in the evening, usually before midnight.
Oviposition begins the next night. Eggs are laid in small groups on the leaves of
the host, whereas the early instars are gregarious, the later instars are solitary.
Adults of the second generation are found in late summer. Their progeny, and
usually some of the first-generation progeny, overwinter as pupae.
Status: Common at times, but scarce at the northern limits of its range. This
species occurs where there are good stands of tulip trees. In Illinois, it is found
in the southern part of the state, north up the Wabash Valley to Crawford
County.
64
Tulip Tree Silkmoth
Reared male Tulip Tree Silkmoth, Pope County.
Reared female Tulip Tree Silkmoth, Pope County.
65
1
Field Guide to Silkmoths of Illinois
Reared Tulip Tree Silkmoth larvae (early
instar), Pope County.
Reared Tulip Tree Silkmoth larvae (2nd
instar), Pope County.
Reared Tulip Tree Silkmoth larva (5th instar,
side view showing lateral stripe), Pope
County.
Reared Tulip Tree Silkmoth
cocoon, Pope County.
66
Tulip Tree Silk Moth
Reared male Tulip Tree Silkmoth (disturbed position), Pope County.
Reared male Tulip Tree Silkmoth (underside), Pope County.
67
Field Guide to Silkmoths of Illinois
Reared female Tulip Tree Silkmoth (disturbed position), Pope County.
Reared female Tulip Tree Silkmoth
(underside), Pope County.
Tulip Tree Moth
Callosamia angulifera
E23 published records
® unpublished records in the
INHS Insect Collection
B sight records by
Bouseman and
Stemburg
■ Dlinois State
Museum
records
68
Cecropia Moth or Robin Moth Subfamily: Saturniinae
Hyalophora cecropia (Linnaeus, 1758)
This imposing moth is probably recognizable and known to more people than
any other North American moth species. It is common over much of its range,
and because of the relatively easy collection of its conspicuous winter cocoons,
it is often brought into the classroom for study. In size, its wings have a greater
total expanse in area than any of our other species, although the Cecropia may be
exceeded in wingspan as measured from wing tip to wing tip by the Regal Moth.
Description of Adult: Wingspan 1 10-150 mm (4 1/4-6 in.) occasionally
larger. One female specimen in the INHS collection has a total extended
wingspan of 7 1/8 in. Sexes are alike in color. As is typical of the family, males
have more broadly quadripectinate antennae than the females. The apex of the
forewing has a violet patch. Behind this is a black spot with a blue inner
margin. The outer margins of the wings are tan or grayish buff. A postmedial
broad white line runs across both the fore and hindwing. Basad of the postme¬
dial line the wings are black, dusted with a scattering of white scales imparting a
grizzled appearance. Each wing has a lunate eyespot, often white, but some¬
times suffused with orange-red. Distad of the postmedial line each wing has a
broad red band, and beyond this a black band. Some individuals have the basal
half of each wing broadly shaded with red-brown scales. All in all, this is a
striking and magnificent insect. In addition to the wing colors, the body is red
with white abdominal circular bands.
Similar Species: The Columbia Moth is much smaller and lacks red markings.
Description of Larva: Length to 100 mm (4 in.). First larval instar is black.
The second instar is yellow. The third, fourth, and fifth instars are green with
red or orange paired scoli on the meso- and metathoracic segments. All dorsal
abdominal scoli are yellow. Lateral scoli are blue.
Similar Species: The Columbia Silkmoth has three pairs of red dorsal scoli
instead of two pairs (two pairs thoracic, one pair first abdominal). Its scoli are
more intensely red. Lateral scoli are white, not blue.
Description of Pupa and Cocoon: Pupae have a smooth brown integument.
There is no cremaster. Cocoons are double-walled with an escape valve.
Freshly spun cocoons are brownish, gradually becoming gray with time. Two
forms occur: Most cocoons are elongate and quite firm, but some are baggy for
reasons not understood; these have the outer layer loose, connected by silken
threads passing through an open region between the outer and inner layers. The
different types do not reflect sexual differences. Baggy cocoons are more
frequent in brushy situations.
69
Field Guide to Silkmoths of Illinois
Habitat: Forests in rural and urban areas, most frequently in areas in the earlier
stages of plant succession.
Natural History: Univoltine with a bimodal emergence. In east-central Illinois
from 5 to 20 percent of overwintering pupae terminate diapause and begin to
develop as soon as spring temperatures rise. These become adults in May. The
remaining 80 to 95 percent require an additional warm period of a month or
more before diapause ends and adult development occurs. The latter moths,
which are most numerous, emerge in late June and early July. Laboratory
experiments have shown that termination of diapause in the late emerging moths
can be triggered by injection of the insect hormone ecdysone, thus bypassing the
need for additional warm temperature to break diapause. Bimodal emergence is
found in all Illinois populations of Cecropia Moth, although the time between
emergences may vary. Under normal conditions, the progeny of one mated pair
will be mixed, some early and some late. By selection during rearing, it is
possible to develop strains with almost all individuals emerging early.
Emergence from the cocoon is usually in late morning. The moth remains
quiet until dusk when the males begin a dispersal flight lasting an hour or more.
The females remain still until pheromone release begins in the last few hours
before dawn. It is during this time that males again become active, seeking
females by flying upwind along odor trails to locate the signaling female.
Mating takes place with no courtship. A mated pair, unless disturbed, will
remain coupled until that evening, when they separate and oviposition begins.
Eggs are laid in masses of 2 to about 10, normally on the larval host. However,
in captivity a female will lay her eggs in an enclosure such as a paper bag,
without any plant material present. Adults survive for a week to 12 days and
then die as their stored energy reserves are depleted. First and second larval
instars are gregarious but later instars disperse to feed solitarily. Larvae are very
polyphagous. A partial list of the more important plants fed upon includes apple
(Malus spp.), birch ( Betula spp.), box elder ( Acer negundo ), buckthorn ( Rham -
mis spp.), dogwoods ( Cornus spp.), garden peony ( Paeonia officinalis), larch
( Larix spp.), poplars ( Populus spp.), rose ( Rosa spp.), silver maple (Acer
saccharinum ), wild cherries (Prunus spp.), willows (Salix spp.), and many
others. When fully grown, larvae empty the gut and actively search for a place
to spin a cocoon. This will often be on a nearby plant, or in vegetation at the
base of the larval host. Some larvae remain in the tree and spin there, but most
cocoons are found hidden in tufts of grass or other plants at the base of the tree.
The location of a cocoon is an important factor in survival. Cocoons visible on
the branches or trunk of a woody plant are subject to winter predation by
woodpeckers. Observation in Urbana-Champaign showed that 90 percent were
attacked by woodpeckers during the winter and early spring months. Cocoons
spun low and hidden were subject to predation in rural areas by white-footed
mice. In the residential areas where house mice are dominant, low cocoons
70
Cecropia Moth
usually escaped predation, due to the inability of house mice to open cocoons.
Cecropia Moth populations are often most dense in areas in an early succes-
sional stage, where trees and bushes are small. As trees mature, and with more
birds present, Cecropia numbers decrease. The flight of the Cecropia is swift
and powerful. We have records of flights of eight miles in one night by marked
individuals from the release point. The species is thus well adapted to disperse
and establish new populations in recently disturbed areas, in an early stage of
succession. In Illinois, new residential areas, built on former cropland, often
furnish ideal conditions for the Cecropia Moth.
Status: Statewide. Considered common, although relative to most insects their
numbers are low. Their large size and bright colors often attract attention, and
the ease with which cocoons can be found ensures familiarity with the species
by many people.
Reared Cecropia Moth larva (4th instar). Reared Cecropia Moth larva (5lh instar),
Champaign County. Champaign County.
Reared Cecropia Moth cocoon slit open to
Reared Cecropia , , , , ,,
v show double wall, Champaign County.
Moth cocoon,
Champaign County.
Reared Cecropia Moth
pupa. Champaign
County.
71
Field Guide to Silkmoths of Illinois
Reared male Cecropia Moth, Champaign County.
Reared female Cecropia Moth, Champaign County.
72
Cecropia Moth
Reared male Cecropia Moth (distrurbed position), Champaign County.
Reared female Cecropia Moth (disturbed position), Champaign County.
Reared Cecropia Moth cocoons
(baggy form on left and compact
form), Champaign County.
73
Field Guide to Silkmoths of Illinois
Reared female Cecropia Moth (resting position), Champaign County.
Cecropia Moth mated pair (female on
right), Champaign County.
Cecropia Moth
Hyalophora cecropia
E3 published records
■ unpublished records in the
INHS Insect Collection
81 sight records by
Bouseman and
Stemburg
■ Illinois State
Museum
records
74
Columbia Silkmoth Subfamily: Saturniinae
Hyalophora Columbia Columbia (S.I. Smith, 1865)
Note: Not recorded from Illinois. It occurs in Wisconsin and Michigan in
tamarack bogs. These bogs occur in a few sites in northern Illinois.
Description of Adult: Wingspan 80-100 mm (3 1/8—4 in.). Sexes similar in
color. The pattern is similar to that of the Cecropia Moth. A white postmedial
line crosses both pairs of wings. The basal region is melanic or dark with a
maroon color. The lunate discal eyespots are white. The wings distad of the
postmedial line are blackish, with no trace of red.
Similar Species: Except for dwarfed individuals H. cecropia is much larger,
and has prominent red postmedian bands, lacking in H. c. Columbia.
Description of Larva: Length to 75 mm (3 in.). First instars are black, second
instars are yellow, and later instars are green with paired red dorsal scoli on the
mesothorax, the metathorax, and the first abdominal segments. The following
dorsal scoli are yellowish. Lateral scoli are white with a black base.
Similar Species: Larvae of H. cecropia are larger when full grown, with only
the two pairs of thoracic scoli reddish or orange. The other dorsal scoli are
yellow, and the lateral scoli blue.
Description of Pupa and Cocoon: Pupation is within a double-walled silken
cocoon with an escape valve. Its color is dark gray with silver and gold stria-
tions. It is often on the larval host, tamarack, but because the prepupal larva
often wanders before spinning, it is often spun upon a nonhost plant. Cocoons
are spun on the branches or the trunk if on a small tree. The pupa is smooth-
bodied, with no cremaster, and is typical of the Saturniinae.
Habitat: Tamarack bogs ( Larix laricina).
Natural History: The Columbia Silkmoth is closely associated with tamarack,
the American larch, which is the primary larval host throughout the moth’s
range. There are reports from a limited number of sites of feeding by larvae on
pin cherry ( Prunus pennsylvanicus), alder ( Alnus rugosa), and white birch
(. Betula papyrifera). In captivity, larvae are said to accept wild black
cherry (. Prunus serotina ), and they do very well on European larch {Larix
decidua ). JGS and colleages maintained a captive culture on the latter for four
generations in the 1970s. The species is univoltine throughout its range from
Maine and Quebec west to the Plains and south to northern Wisconsin, Michi¬
gan, New York, and east. Emergence in the spring is early, usually in May or
75
Field Guide to Silkmoths of Illinois
June depending upon latitude. The flight season lasts several weeks, the timing
varying within any site depending on local weather patterns. Emergence from
the cocoon is in midmoming. Males search for females near dawn, at which time
mating takes place. The mated pair then remains quiet until that night, when
they separate. The females then begin oviposition; the eggs are laid singly or in
small groups on the bases of the larch needles. They hatch in 10 days or so.
The larvae disperse to feed singly until mature in mid to late summer. There are
five instars. As stated above, cocoons are spun on the branches of the larval
host, or on nearby vegetation.
Status: The Columbia Silkmoth is not known to occur in Illinois, but is
included here for comparison and because it occurs in northern Wisconsin and in
lower Michigan. There are a few tamarack bogs in northern Illinois and a
chance stray female could conceivably produce a temporary population.
Remarks: The subspecies H.c. gloveri (Strecker, 1872) occurs west of the
range of H .c. Columbia and south through the Rocky Mountains. Its larvae feed
on willows and poplars.
Reared Columbia Silkmoth larvae (2nd
instar), Lower Michigan.
Reared Columbia Silkmoth larva (1st
instar), Lower Michigan.
Reared Columbia Silkmoth larva (5th instar,
dorsal view), Lower Michigan.
Reared Columbia Silkmoth larva (5th instar,
side view), Lower Michigan.
Reared Columbia Silkmoth
cocoon, Lower Michigan.
76
Columbia Silkmoth
Reared female Columbia Silkmoth, Lower Michigan.
Reared male Columbia Silkmoth, Lower Michigan.
77
Field Guide to Silkmoths of Illinois
Reared female Columbia Silkmoth (disturbed position), Lower Michigan.
Reared female Columbia Silkmoth (resting postion), Lower Michigan.
78
Columbia Silkmoth
Columbia Silkmoth mate pair (female above), Lower Michigan.
79
Field Guide to Silkmoths of Illinois
Ailanthus Silkmoth Subfamily: Saturniinae
Samia cynthia (Drury, 1773)
Description of Adult: Sexes alike. Wingspan 100-1 15 mm (4-4 1/2 in.).
Wings olive-brown with a lunate whitish discal spot on each wing. A sinuous
white postmedial line, bordered on the basal side with black and outwardly with
pink, runs across the fore and hindwings. There is a violet area at the apex of the
forewing and a black-and-white eyespot. The abdomen has rows of white spots.
The wings of the male are more pointed than the broader, more rounded wings
of the female. The rami of the quadripectinate antennae are longest in the male.
Similar Species: None in Illinois.
Description of Larva: Length to 75 mm (3 in.). Color of larger larvae bluish
green. Body with black dots and black spiracles, with three rows of scoli,
dorsal, supraspiracular and subspiracular. On the later instars a whitish bloom
covers the scoli and sometimes extends over the body.
Description of Pupa and Cocoon: The pupa is typical of the attacine satumi-
ids. It is protected by a double-walled silken cocoon spun among the leaflets of
an Ailanthus leaf. When the leaf stem eventually falls the cocoon drops to the
ground, where it overwinters.
Habitat: Urban areas where tree-of-heaven ( Ailanthus altissima ) grows,
typically railroad yards, against city fences, in vacant lots, depressed areas, city
parks.
Natural History: Either univoltine or bivoltine depending on geographic
location. The species overwinters as a pupa within a cocoon on the ground.
Adults emerge in May and June. Eclosion of the adults is during the late
morning hours. Mating takes place that day after dark. Oviposition begins the
next evening. Larvae feed on the leaves of tree-of-heaven (Ailanthis altissima ),
rarely on other species.
Status: Not known to be established in Illinois. However, the species has been
reported from Kentucky and St. Louis, Missouri. We know of no authentic
Illinois specimens, but include the species because of the possibility of introduc¬
tion. Occasional releases by breeders may occur, and are said to have occurred
historically.
Remarks: The Ailanthus Silkmoth was deliberately released around 1860 in
Philadelphia and other cities for the purpose of sericulture, an industry that
failed in the U.S. The species is reared for its silk to a limited extent in Asia. Its
present distribution in the U.S. appears to be declining.
80
Ailanthus Silkmoth
Reared male Ailanthus Silkmoth, from commercial source.
Female Ailanthus Silkmoth, Brooklyn, NY.
81
Field Guide to Silkmoths of Illinois
Male Ailanthus Silkmoth.
Reared Ailanthus Silkmoth
larva (late instar), from
commercial source.
82
Glossary
Allopatric
not occurring together geographically
Amplexiform
wing coupling for flight by means of overlapping
wings
Attacine
belonging to the satumiid tribe Attacini
Basad
toward the base of an appendage or toward the body
Batesian mimicry
mimicry when the model is unpalatable, poisonous,
or dangerous, and the mimic is palatable and harm¬
less
Bipectinate
with each antennal segment bearing two branches
Bivoltine
two generations per year
Cremaster
a hooked structure at the tip of the last segment of a
pupa
Crochets
small, hard cuticular hooks on the larval prolegs used
to cling to surfaces
Diapause
arrested development, in response to environmental
cues and controlled by hormonal changes
Diurnal
active during daylight hours
Dimorphic
with two forms
Discal cell
a cell at the base of a wing
Ecdysis
process of shedding the insect’s cuticle
Ecdysone
a hormone controlling metamorphosis
Eclosion
emergence, as from a shed insect cuticle or cocoon
Frenulum
a bristle or bristles of the hindwing used to couple the
wings in flight
Humeral angle
expanded basal margin of hindwing often involved in
amplexiform wing coupling
83
Instar
Field Guide to Silkmoths of Illinois
the insect itself between molts
Labium
fused second maxillae, the appendage of the fourth
postoral head segment
Mandible
one of a pair of appendages of the second, postoral
head segment used in feeding primitively for chewing
Maxilla
one of a pair of appendages of the third postoral head
segment, used as an adjunct to the mandibles in
feeding
Medial
located midway from the wing base
Mullerian mimicry
when two or more unpalatable, poisonous, or
dangerous species have evolved similar form, color,
or behavior
Multivoltine
two or more generations per year
Nocturnal
active at night
Pheromone
a substance produced by one individual that causes a
response by another individual within the same
species
Polyphagous
feeding on many different plant species
Postmedial
located distad of the medial area of a wing
Proleg
an abdominal leg of a lepidopterous larva, bearing
distal hooks
Quadripectinate
with four branches per antennal segment
Ramus
one of the branches of a pectinate antennal segment
Retinaculum
a structure of the forewing that functions as a clasp
for the frenulum during wing coupling
Scolus
a tubercle bearing setae or spines found on lepi¬
dopterous larvae
Stemmata
(singular stemma) larval eyes of a caterpillar, usually
in a semicircle of six on the lower sides of the
cranium
Sympatric
occurring together geographically
84
Species Checklist
For common names we have followed Covell, A Field Guide to the Moths of
Eastern North America. We have used the generic name Syssphinx, following
Lemaire.
Family Saturniidae
Subfamily Ceratocampinae
Citheronia regalis (Fabricius, 1793)
- Regal Moth or Royal Walnut Moth
Citheronia sepulchralis Grote and Robertson, 1865
- Pine-devil Moth
Eacles imperialis (Drury, 1773)
- Imperial Moth
_ Anisota stigma (Fabricius, 1775)
Spiny Oakworm Moth
_ Anisota virginiensis (Drury, 1773)
Pink-striped Oakworm Moth
_ Anisota senatoria (J.E. Smith, 1797)
Orange- striped Oakworm Moth
_ Dryocampa rubicunda (Fabricius, 1793)
Rosy Maple Moth
_ Syssphinx bisecta (Lintner, 1879)
Bisected Honey Locust Moth
_ Syssphinx bicolor (Harris, 1841)
Honey Locust Moth
Subfamily Hemileucinae
_ Hemileuca maia maia (Drury, 1773)
Buck Moth
85
Field Guide to Silkmoths of Illinois
_ Hemileuca nevadensis Stretch, 1872
Nevada Buck Moth
_ Automeris io (Fabricius, 1775)
Io Moth
Subfamily Saturniinae
_ Antheraea polyphemus (Cramer, 1776)
Polyphemus Moth
- Actias luna (Linnaeus, 1758)
Luna Moth
- Calloscimia promethea (Drury, 1773)
Promethea Moth or Spicebush Silkmoth
_ Callosamia angulifera ( Walker, 1885)
Tulip Tree Silkmoth
_ Hyalophora cecropia (Linnaeus, 1758)
Cecropia Moth or Robin Moth
- Hyalophora Columbia Columbia (S.I. Smith, 1865)
Columbia Silkmoth
- Sarnia cynthia (Drury, 1773)
Ailanthus Silkmoth
86
Additional Reading
Field Guides
Covell, C.V., Jr. 1984. A field guide to the moths of eastern North America.
Houghton Mifflin Company, Boston, xv + 496 pp.
Kricher, J.C., and G. Morrison. 1980. A field guide to eastern forests.
Houghton Mifflin Company, Boston, xviii + 368 pp.
Lutz, F.E. 1948. Field book of insects of the United States and Canada, aiming
to answer common questions. 3d ed. G.P. Putnam's Sons, New York. 510 pp.
Milne, L., and M. Milne. 1980. National Audubon Society field guide to North
American insects and spiders. Alfred A. Knopf, New York. 989 pp.
Faunal Works
Coveil, C.V., Jr. 1999. The butterflies and moths (Lepidoptera) of Kentucky:
an annotated checklist. Kentucky State Nature Preserves Commission Scientific
and Technical Series No. 6. xiv + 220 pp.
d’ Abrera, B. 1995. Saturniidae mundi. Satumiid moths of the world. Part I.
Automeris Press, Keltern, Germany. 177 pp.
d’ Abrera, B. 1998. Saturniidae mundi. Saturniid moths of the world. Part III.
Goecke & Evers, Keltern, Germany. 171 pp.
Heitzman, J.R., and J.E. Heitzman. 1987. Butterflies and moths of Missouri.
Missouri Department of Conservation, Jefferson City, viii + 385 pp.
Metzler, E.H. 1980. Annotated checklist and distribution maps of the royal
moths and giant silkworm moths (Lepidoptera: Saturniidae) in Ohio. Ohio
Biological Survey Biological Notes No. 14. iv + 10 pp.
Opler, P.A. 1995. Lepidoptera of North America. 1. Distribution of silkmoths
(Saturniidae) and hawkmoths (Sphingidae) of eastern North America. Contribu¬
tions of the C.P. Gillette Museum of Insect Biodiversity, Department of Ento¬
mology, Colorado State University, Fort Collins. (Unpaginated).
87
Field Guide to Silkmoths of Illinois
Classification
Ferguson, D.C. 1971. Fascicle 20. 2A, Bombycoidea (in part). Pages 1-153 in
R.B. Dominick et al. The moths of North America north of Mexico. E.W.
Classey, London.
Ferguson, D.C. 1972. Fascicle 20. 2B, Bombycoidea (in part). Pages 155-275
in R.B. Dominick et al. The moths of North America north of Mexico. E.W.
Classey, London.
Lemaire, C. 1978. Les Attacidae americains. Attacinae. Lemaire, Neuilly-sur-
Seine. 238 pp. + 49 pis.
Lemaire, C. 1988. Les Satumiidae americaines. Ceratocampinae. Museo
Nacional de Costa Rica, San Jose. 480 pp. + 64 pis.
Lemaire, C., and J. Minet. 1999. The Bombycoidea and their relatives. Pages
321-353 in N.P. Kristensen, ed. Handbook of zoology, Vol. IV, Arthropoda:
Insecta. Part 35, Lepidoptera, moths and butterflies. Vol. 1: Evolution, system-
atics, and biogeography. Walter de Gruyter, Berlin and New York.
Michener, C.D. 1952. The Satumiidae (Lepidoptera) of the Western Hemi¬
sphere. Morphology, phylogeny, and classification. Bulletin of the American
Museum of Natural History 98:335-502.
Natural History
Ford, E.B. 1972. Moths. 3d ed. Collins, London, xix + 266 pp.
Klots, A.B. 1958. The world of butterflies and moths. McGraw-Hill Book
Company. New York, Toronto, London. 207 pp.
Leverton, R. 2001. Enjoying moths. T. & A.D. Poyser Ltd., London, xi + 276 pp.
Scoble, M.J. 1992. The Lepidoptera: form, function, and diversity. Oxford
University Press, New York and Oxford, xi + 404 pp.
Tuskes, P.M., J.P. Tuttle, and M.M. Collins. 1996. The wild silk moths of
North America: a natural history of the Satumiidae of the United States and
Canada. Cornell University Press, Ithaca and London, ix + 250 pp.
Vesco, J.P. 2001. Moths and butterflies. Viking Studio, Penguin Putnam, New
York. 183 pp.
88
Additional Reading
Young, M. 1997. The natural history of moths. T. & A.D. Poyser Ltd.,
London, xiv + 271 pp.
Immature Stages
Godfrey, G.L., M. Jeffords, and J.E. Appleby. 1987. Satumiidae
(Bombycoidea). Pages 513-521 in F.W. Stehr, ed. Immature insects. Vol. I.
Kendall Hunt Publishing Company, Dubuque, Iowa, xiv + 754 pp.
Mosher, E. 1969. Lepidoptera pupae. Five collected works on the pupae of
North American Lepidoptera. Entomological Reprint Specialists, East Lansing,
Michigan, vii + 323 pp.
Tietz, H.W. 1972. An index to the described life histories, early stages and
hosts of the Macrolepidoptera of the continental United States and Canada.
A.C. Allyn, Sarasota, Florida, iv + 1041 pp. (Bound in two volumes).
Wagner, D.L., V. Giles, R.C. Reardon, and M.L. McManus. 1997. Caterpillars
of eastern forests. United States Department of Agriculture Forest Service,
Forest Health Technology Enterprise Team Publ. No. 96-34. United States
Government Printing Office, Washington, DC. 113 pp.
Rearing
Collins, M.M., and R.D. Weast. 1961. Wild silk moths of the United States.
Satumiinae. Collins Radio Company, Cedar Rapids, Iowa, iii + 138 pp.
Stone, S.E. 1991. Foodplants of world Satumiidae. The Lepidopterists’ Society
Memoir 4. xv + 186 pp.
Villiard, P. 1969. Moths and how to rear them. Funk & Wagnalls, New York,
xiii + 242 pp.
Winter, W.D., Jr. 2000. Basic techniques for observing and studying moths and
butterflies. The Lepidopterists’ Society Memoir 5. xviii + 444 pp.
Economic Considerations
Johnson, W.T., and H.H. Lyon. 1991. Insects that feed on trees and shrubs: an
illustrated practical guide. 2d ed., revised. Comstock Publishing Associates,
Ithaca, New York. 560 pp.
89
Field Guide to Silkmoths of Illinois
Metcalf, R.L., and R.A. Metcalf. 1993. Destructive and useful insects: their
habits and control. 5th ed. McGraw-Hill. New York, xv + unpaginated.
United States Department of Agriculture Forest Service. 1985. Insects of
eastern forests. USDA Forest Service Miscellaneous Publication No. 1426.
United States Government Printing Office, Washington, DC. x + 608 pp.
Photography
Angel, H. 1982. The book of nature photography. Alfred A. Knopf, New
York. 168 pp.
Fitzharris, T. 1990. The Audubon Society guide to nature photography. Little,
Brown and Company, Boston, Toronto, London. 167 pp.
Shaw, J. 1984. The nature photographer’s complete guide to professional field
techniques. Watson-Guptill Publications, New York. 144 pp.
Shaw, J. 1987. John Shaw’s close-ups in nature. Watson-Guptill Publications,
New York. 144 pp.
Shaw, J. 1991. John Shaw’s focus on nature. Watson-Guptill Publications,
New York. 144 pp.
Botanical References
Braun, E.L. 1967. Deciduous forests of eastern North America. Hafner
Publishing Company, New York and London, xiv + 596 pp.
Leopold, D.J., W.C. McComb, and R.N. Muller. 1998. Trees of the central
hardwood forests of North America: an identification and cultivation guide.
Timber Press, Portland, Oregon. 469 pp.
Mohlenbrock, R.H. 1986. Guide to the vascular flora of Illinois. Revised and
enlarged ed. Southern Illinois Press, Carbondale and Edwardsville. viii + 507
pp.
Mohlenbrock, R.H. 1996. Forest trees of Illinois. 8th ed. Illinois Department
of Natural Resources, Springfield. 331 pp.
90
Additional Reading
Petrides, G.A. 1988. A field guide to eastern trees. Houghton Mifflin Com¬
pany, Boston, xv + 272 pp.
Recreational Reading
Cody, J. 1996. Wings of paradise: the great satumiid moths. University of
North Carolina Press, Chapel Hill & London, xix + 163 pp.
Holland, W.J. 1903. The moth book: a popular guide to a knowledge of the moths of
North America. Doubleday, Page & Company, New York, xxiv + 479 pp.
Matthews, P. 1957. The pursuit of moths and butterflies: an anthology. Chatto
& Windus, London. 141 pp.
Stratton-Porter, G. 1912. Moths of the Limberlost. Doubleday, Page &
Company, Garden City, New York, xiv + 370 pp.
Waldbauer, G. 1996. Insects through the seasons. Harvard University Press,
Cambridge, Massachusetts and London, England, xiii + 289 pp.
De Omnibus Rebus
Boettner, G.H., J.S. Elkinton, and C.J. Boettner. 2000. Effects of a biological
control introduction on three nontarget native species of satumiid moths.
Conservation Biology 14(6): 1798-1 806.
Hodges, R.W., et al.,eds. 1983. Check list of the Lepidoptera of America north
of Mexico. E.W. Classey Limited, London, and The Wedge Entomological
Research Foundation, Washington, DC. xxiv + 284 pp.
Jeffords, M.R., G.P. Waldbauer, and J.G. Stemburg. 1980. Determination of
the time of day at which diurnal moths painted to resemble butterflies are
attacked by birds. Evolution 34(6): 1205-121 1.
Jensen, M.N. 2000. Silk moth deaths show perils of biocontrol. Science
290:2230-2231.
Stemburg, J.G., and G.P. Waldbauer. 1969. Bimodal emergence of adult
cecropia moths under natural conditions. Annals of the Entomological Society
of America 626(6): 1422-1429.
91
Field Guide to Silkmoths of Illinois
Stemburg, J.G., and G.P. Waldbauer. 1978. Phenological adaptations in
diapause termination by cecropia from different latitudes. Entomologia
Experimentalis et Applicata 23:48-54.
Stemburg, J.G., and G.P. Waldbauer. 1984. Diapause and emergence patterns
in univoltine and bivoltine populations of promethea (Lepidoptera: Satumiidae).
The Great Lakes Entomologist 17(3): 155-1 61.
Stemburg, J.G., G.P. Waldbauer, and M.R. Jeffords. 1977. Batesian mimicry:
selective advantage of color pattern. Science 195:681-683.
Stemburg, J.G., G.P. Waldbauer, and A.G. Scarbrough. 1981. Distribution of
cecropia moth (Satumiidae) in central Illinois: a study in urban ecology. Journal
of the Lepidopterists’ Society 35(4):304-320.
Waldbauer, G.P., and J.G. Stemburg. 1967. Differential predation on cocoons
of Hyalophora cecropia (Lepidoptera: Satumiidae) spun on shrubs and trees.
Ecology 48(2):3 12— 3 15.
Waldbauer, G.P., and J.G. Stemburg. 1973. Polymorphic termination of
diapause by cecropia: genetic and geographical aspects. Biological Bulletin
145:627-641.
Waldbauer, G.P., and J.G. Stemburg. 1978. The bimodal termination of
diapause in the laboratory by Hyalophora cecropia. Entomologia
Experimentalis et Applicata 23:121-130.
92
Index
Acer 24, 34, 46, 49, 59
Acer negundo 70
Acer rubrum 34
Acer saccharinum 34, 70
Acer saccharum 34
Actias luna 6, 53-57
Ailanthus altissima 80
Ailanthus Silkmoth 80-82
Alder 75
Alnus rugosa 75
Anisota 6, 28
Anisota senatoria 30, 32-33
Anisota stigma 28-30, 32
Anisota virginiensis 30-32
Antennae 3, 6-7
Antheraea polyphemus 6, 48-52
Apatelodinae 3
Apple 45, 49, 70
Ash 59
Automeris io 45-47
Basswood 45
Batesian mimicry 10, 58-59, 83
Battus philenor 10, 58-59
Betula 24, 43, 49, 70
Betula papyrifera 54, 75
Betula pumila 43
Birches 24, 49, 70
Bisected Honey Locust Moth 36-38
Blackberry 45
Black cherries 45, 59, 75
Bogbean 43
Bombycidae 3
Bombycoidea 3
Box elder 70
Buck Moths 2—4, 6-7, 41-43
Buckthorn 70
Callosamia angulifera 58, 64, 68
Callosamia promethea 10, 58, 63, 64
Carya 18, 46, 53
Cecropia Moth 7, 8, 1 1-12, 69-75
Celtis 45
Field Guide to Silkmoths of Illinois
Ceratocampinae 6, 17, 22, 24, 28, 30, 32, 34, 36, 38
Cercis canadensis 46
Cherries 49, 70
Citheronia regalis 17-18, 21-22
Citheronia sepulchralis 22
Classification 3^1
Columbia Silkmoth 5, 69, 75-79
Corn 45
Cornus 49, 70
Corylus 28, 41
Diospyros virginiana 18, 54
Distribution of Silkmoths 2
Dogwood 49, 70
Dryocampa rubicunda 10, 34-35
Dwarf birch 43
Eacles 6
Eacles imperialis 6, 24-27
Economic Considerations 2
Elm 45, 49
European larch 75
Family Saturniidae 1-3
Fraxinus 59
Garden peony 70
Geometrid 6
Geometridae 6
Gleditsia triacanthos 36, 38
Green-striped Mapleworm 35
Gymnocladus dioicus 36, 38
Hackberry 45
Hawkmoths 2
Hazel 28, 41
Hemileuca 3, 41, 43
Hemileuca maia maia 10, 41-43
Hemileuca nevadensis 10, 41-44
Hemileucinae 6, 41, 43, 45
Hickory 18,46,53
Hickory Homed Devils 17
Honey Locust Moth 38-40
Honey locust tree 36, 38
Hyalophora cecropia 69-74
Hyalophora Columbia Columbia 75-79
Hyalophora Columbia gloveri 76
Hyparpax aurora 10, 34
Illinois Natural History Survey 2
94
Index
Illinois State Museum 2
Imperial Moth 6-7, 24-27
Io Moth 2, 6-7, 45-47
Juglans 18, 24, 49, 53
Kentucky coffee tree 36, 38
Larch 70, 75
Larix 70, 75
Lari: c decidua 75
Larne laricina 75
Larval Morphology 4
Lepidoptera 3^1
Ligustrum 46
Lilac 59
Limacodidae 6
Linder a 59
Liquidambar styracflua 18, 54, 59
Liriodendron tulipifera 59, 64
Luna Moth 8-9, 53-57
Lythrum salicaria 43
Malus 45, 49, 70
Mandibles 4-5
Maples 24, 34, 46, 49, 59
Maps of Distribution 2
Menyanthes trifoliata 43
Mice 70-71
Mimicry 10, 34
Moon Moth 54
Moth Pupae 7
MUllerian mimicry 43
Neotropical Royal Moth 10
Nevada Buck Moth 41, 43-44
Notodontidae 34
Nymphalidae 6
Oak 24, 28, 30, 32, 34, 41, 43-44, 46, 49
Orange- striped Oakworm Moth 32-33
Paeonia officinalis 70
Papilio glaucus 59
Persimmon 18, 54
Pin cherry 75
Photographing Insects 12
Pine-devil Moth 22-23
Pink Prominent Moth 10, 34
Pink-striped Oakworm Moth 28, 30-32
Pinus 24
Field Guide to Silkmoths of Illinois
Pinus rigida 22
Pinus strobus 22
Pinus virginiana 22
Pipevine Swallowtail 10, 58-59
Plums 49, 70
Polyphemus Moth 7, 1 1, 48-52
Poplars 42-43, 46, 49, 70
Populus 42-43, 46, 49, 70
Primrose Moth 6, 10-1 1, 34
Privet 46
Promethea Moth 4, 8, 10-11, 58-64
Prunus 49, 70
Prunus pennsylvanicus 75
Prunus serotina 45, 59, 75
Psilopygida apollkinairei 10
Purple loosestrife 43
Quercus 24, 28, 30, 32, 34, 41, 46, 49
Quercus ilicifolia 41, 43
Redbud 46
Regal Moth 17-22, 69
Rhamnus 70
Rhus 18, 54, 59
Robin Moth 69
Rosa 49, 70
Rose 49, 70
Rosy Maple Moth 2, 34-35
Royal Walnut Moth 17
Rubus 45
Salix 42-43, 46, 49, 70
Salt Marsh Caterpillar Moth 42
Samia cynthia 80
Sassafras 24, 46, 59
Sassafras albidum 24, 46, 59
Satumiid 1-6, 11-13, 17, 30, 32, 34, 54, 80
Satumiid Relatives 14
Satumiidae 1-3, 6, 59
Satumiinae 6-8, 48, 53, 58, 64, 69, 75, 80
Schinia florida 10, 34
Scrub oak 43
Silver maple 70
Species Checklist 85
Sphingicampa 36
Sphingidae 2-3
96
Index
ACES r£ferencf
Spicebush 59
Spicebush Silkmoth 58
Spiny Oakworm Moth 28-29
Subspiracular scoli 5
Sumac 18, 54, 59
Swallowtail 10, 58-59
Sweet gum 18, 54, 59
Syringa 59
Syssphinx bicolor 30, 36, 38-40
Sys sphinx bisecta 36-38
Tamarack bogs 75-76
Tiger Swallowtail 59
Tilia 45
Tree-of-heaven 80
Tulip tree 59, 64
Tulip Tree Silkmoth 64-68
Ulmus 45, 49
Walnut 18, 24, 49, 53
White Birch 54, 75
Willows 42-43, 46, 49, 70
Wing vein terms 4
Zea mays 45
97
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